Is it appropriate to confront a higher rank when they are blatantly disregarding regs?

A person in contrast with regulation should be made aware that they are in violation. You may tactfully confront them or request a person holding higher rank to confront and advise them. I am sure the Major General and his or her aides noticed the violation. The violation may be minor, but she is flaunting her disregard for rank and regulation. If she wants to retain rank she has to respect rank. I was Army and understand each branch have their own way of dealing with appearance violations...that said, a First Sgt. or C.M. Sgt. would take immediate and direct action.

No, ONE Does NOT CONFRONT an individual of a higher rank, however, it is the obligation of all soldiers, regardless of rank, to uphold the integrity and good discipline of the military, so it is absolutely acceptable for a person of a lower rank to make the senior aware of the violation, or behavior which has a negative reflection of the military. Those who are not NCO'es, I understand their hesitancy or not doing so, but if you are an NCO or above, one actually has an obligation to address the issue. Do not do it disrespectfully, do it with tact, professionalism, and most of all, make certain you know what you are talking about when addressing the issue.

When I was on I&I duty in Texas the reserve unit got a new Colonel as their CO, I was a Gunnery Sergeant. At his first conference with his staff I was present. My desk was at the end of the conference table. When he finished talking he ask if anyone had anything for him. He was wearing an ink pen inappropriately on his uniform I advised him before he went out to walk about among the enlisted personnel he needed to remove the ink pen. He said “Is that what you think I should do Gunny?” I explained which Marine Corps uniform regulation he was violating and said “Yes Sir I do and so does the Commandant.” He removed the pen. So in answer to your question, yes it is appropriate but you better have all of your duck in a row and understand their may be repercussions!

Ok, two points I have to make;
First - As a leader; or potential one, everyone in the Military is Obligated to Politely and discretely question the validity of any activity that is, or might be in violation of the UCMJ and Uniform Regulations. One big difference between the Civilian world and the Military one is; the Military trains their replacements.
Second point - and this one frosts me the most: The comments about photographic proof of the 'alleged' infraction. Oh, dear the poor little person (who may have knowingly and willingly been breaking the rules about lipstick color) didn't give their permission to have their picture taken. Yet, they have no problem walking around flaunting their disregard for the reputation of those in the Military as being a Professional Organization both in Appearance as well as in Performance.
Remember a photograph is worth a thousand words and CAN'T be denied (unless it is edited.) In the United States, the citizens are on camera Much more often then most people realize: from ATMs to store cameras to traffic cams to being caught in the background of someone's Facebook entry or webcam pictures. In My opinion: the only valid objection anyone has to their picture being taken is if the 'photographer' makes money from it and doesn't get your permission for that purpose.

Depends on the command. Once (many years ago) I was eating "mid-rats," or rations for those coming off the midnight watch on our submarine. I tried the cottage cheese and it tasted like sawdust. The Chief of the Boat (think CSM) sat down across from me with a big bowl. I told him he wasn't going to like it. He said, "I LOVE this stuff!" I repeated my warning. He took one bite, and went to talk to the cook. I always followed the protocol to get someone higher in rank than me to be upset with the regulation-breaker, without "tattling." The COB got up and went to ask the cook WT*. The cook, who outranked me, wasn't going to talk back to the E-9. He simply pointed to an olive drab paint can, stenciled in black lettering:
"CHEESE, COTTAGE, RECONSTITUTED PACKING DATE JULY 1945."
Unfortunately, and apparently, the cook wasn't actually breaking any regulations. More's the pity. The rations were left over from the invasion of Japan that didn't happen, else it would have been my father (US Army Air Corps) who would have been stuck eating it.

You can correct someone who out ranks you. You need to pull them to the side and be respectful. Just in case, show them what regulation it is and maybe what it says specifically. If they pull rank on you or become disrespectful, get their rank, their name, and their unit (if possible), and use your chain of command. You did what you knew was right; it’s no use fighting over it with that person. Beyond correcting them, there is not much else you can do.

You have three choices: 1) correct her on the spot respectively, 2) find someone of equal or higher rank in chow hall to correct her, 3) do nothing like you did which is wrong.

True story I had this lieutenant over my section that had just got his first lieutenant bars I guess he might have been feeling his oats. I just left the barber for my 2-week haircut I walk into the section and lieutenant tells me to go get a haircut then I'm out of regs. I knew for a fact I wasn't it was summertime and I had them cut it extra close. I acknowledged his order confirm with a couple other non-commissioned officers inquiring if my hair meeting regulations in this received not one single remark to the contrary of meeting regulations. I went about my business 2 weeks later I just came back from the barber shop again and was told by the lieutenant to go get a haircut or be charged with disobeying a direct order. By this time it was getting asinine. On my way out to return to the barber I hit every senior NCO I knew on the way out the door inquiring of my hair meeting regulations I stopped and visit the first sergeant and Commander they both remarked it was fine. I went back to my barber explain to her that I had an anal-retentive lieutenant and she trimmed it again for free. I came back into the unit stop the visit the first sergeant and Commander and explain to them why I had asked them about my haircut and regulations that the lieutenant was insisting I go get another haircut and also that the lieutenant hair was touching his ears and his haircut was out of regulations exception noted dismissed In a respectful manner.. I checked with most of the senior ncos on the way to the Lieutenant's office they all commented it was fine the first time. I met the lieutenant outside his office he commented that's how it's supposed to be. I respectfully said to Lieutenant.." sir could I speak to you in private please" we went into his office and I explained " sir you are an example to the men and women here and I regret to inform you that your hair is touching your ears sir and is out of regulations" the Lieutenant snapped off exception noted dismissed. Which was done in a slightly snarky manner. I went on my Merry way and done my job and done my duty and didn't say anything to anybody else from there. About three weeks later the major got a hold of the lieutenant and I understand he chewed up both cheeks and spit out pieces. The next day the lieutenant came in and they had a Kim Jong Un bowl haircut. His hair was shaved about an inch above his ears all the way down the side of his head. He had an afro and his ears laid close to his head. But his hair didn't touch his ears now.. I had nothing personal against lieutenant but he departed from us about a year later to other pastures. But after the threat I'm being charged with disobeying a direct order and the asinine request to get another haircut after I had a fully compliant haircut was just a little too much. Even if you shaved my head my hair was so thick it look like I didn't have a haircut I was even accused of being out of regulations in basic training because my hair was so thick. They wanted to see scalp and even if you cut it close you couldn't see scalp unless I shaved it and that didn't last for long. Classic rule I can give you is praise in public and criticize in private but from experience take notes cover your ass too much rank has its privileges has run amok and all of the branches and there's no longer a moral turpitude clause in the UCMJ to protect you from a revengeful superior.. that in my opinion is the problem in the military no accountability UP the chain. I've seen far too much corruption in three branches I've served in.

She looks like my last commander
CPT Yun Hee Kim

ABSOLUTELY confront anyone, respectfully, when they are out of regs. They may not even realize they're wrong. Your obligation as a servicemember is to be a Wingman....have their six. Please don't let rank scare you, but be 100% sure you know your regs first.