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

As with anything else, show tact and don't embarrass them as in a gotcha moment. Present your observation and allow them to correct themselves in their own way, It is not for you to do so.

If you use the right amount of politeness and tact to get the point across you can even tell off a 2 Star Flag Officer. My CAG when I was in on my last ship had been in his flight suit with his zipper all the way down to below his chest and was wandering the decks; chatting with other officers including my XO. He had just cited regulations about properly wearing coveralls and other uniforms correctly on board since we had VIPs visiting the carrier that upcoming week.

I looked at him square in the eye and said, "SIR, I though we're supposed to follow you as a good example of leadership?" He looked at his zipper pulled it up to between his chest pockets and shook his head while blushing bright red (as a ginger hiis whole head was red as a tomato). My CMC later on called me out for it in private; but said I pulled off the best call out he heard about. I was able to pull an EPIC WIN on citing the CAG for breaking his own regs.

We used to have a COL who would intentionally wear his uniform improperly and reward the soldier who brought it to his attention. And as others said always be tactful. I was once called to the Battalion Commander's office because the S-3 said I had been disrespectful to him. I had reminded him of an AR he was violating. After I gave my version, and showed him the AR, his exact response was, "Reddick, you got to learn tact."

It is hairy to see a superior violating regulations and wanting to correct them because of the vindictiveness that permeates society in general. So, what's a junior to do? I can think of two choices right off hand. 1-Ask them if it is now permitted to do this or that (although one knows that it violates regulations) or 2-point out the violation to another superior who will then have the onus to make the correction or, at the very least, personally point out the infraction to the violator.

Yes but use tact. Get them away from their peers and keep it professional. Be prepared to show the regulation .

I remember having to address a commissioned officer that was breaking the regs. (He noticed new looking at him and tried making a V line for his car). At first he thanked me being an NCO for being up to letting him know he was messed up (especially since we were on a Tradoc post). Even respectfully thanked him for stopping and talking with me, rendered a salute and was on our way.

Well the next day he sought me out and pulled me off to the side and than decided to tell me that he was thinking about it all night long and decided that my approach was condescending. Thankfully I was with a LTC and let him know the day before this (covering my tracks in the event this would happen Where he would try to come back as I had a weird feeling about him) and informed him that if he would like to talk to the LTC that he informed me that he would be up to speaking to the young officer if there was any issues. The young officer said never mind and thanked me for my time and left. I literally seen this officer and it appeared that he was following me but i made sure he had nothing to approach me for. It shows that you can do it but make sure that you are doing the right thing as well because not all have the integrity to take the heads up, adjust fire and Charlie Mike.

It certainly is. BUT, Be Correct in what you say. Be Tactful in how you say it and be ready for that person to not take it in the spirit you mean it.
You can, by phrasing it as a question, get your point across while not looking like a smart ass. I.E. Staff Sergeant, did they change the regulations about lipstick? I am new and if there was a change I would like to know because I was taught...etc."
Also, I would refrain from posting photos on here, no matter how funny they look

How about" Wow SSgt, have they finally loosened up the regs on lipstick?"

Stay out of those battles. Let the zoo be the zoo.

Absolutely as it is actually mandated by appropriate Branch regulation which comes from the Commander-in-Chief. And like others have said, by not making the correction to correct the deficiency back to the standard, you just lowered the standard by accepting it.

Excerpt from FM 7-21.13:

"...General Military Authority. It originates in oaths of office and enlistment, law, rank structure, traditions, and regulations. This broad-based authority allows leaders to take appropriate corrective actions whenever a member of the armed services commits an act involving a breach of good order and discipline. Army Regulation 600-20, specifically gives this authority to commissioned, warrant, and noncommissioned officers.
b. Exercising Military Authority. Military authority is exercised promptly, firmly, courteously and fairly. Commanders should consider administrative corrective measures before deciding to impose nonjudicial punishment. Trial by court-martial is ordinarily inappropriate for minor offenses unless lesser forms of administering discipline would be ineffective (AR 600-20, paragraph 4-6).
(1) On-the-Spot Corrections. Generally, a Soldier requires an on-the spot correction for one of two reasons: the Soldier does not know the standard, or they knowingly violate the standard. If the latter occurs, the violation should be addressed immediately and when appropriate, should be followed-up with a call to the Soldier's chain of command. On-the-spot corrections are not only issued from the leader to the subordinate, but also include tactful corrections from subordinates to leaders and corrections between peers. It is your responsibility to understand and adhere to the standard."

I agree about using tact, but I would also caution you about posting her picture on this or any other site.