Am I the only one who thinks that some hirings in the federal government are "rigged" by the hiring officials to hire someone they prefer??

Are we talking delegated examination hiring in the competitive service or merit promotion? If it's a regular competitive posting, it's hard to bypass veterans preference and schedule A. This means that even if they have someone picked out, they still need to qualify for special hiring preferences. If it's merit promotion, then vet pref only affords you the right to apply for the job, it does not give you a hiring preference. As such, a current federal employee will likely be chosen over a veteran not yet in the federal service.

No, you are not imagining things. The system can be played to get the candidate you want into the job. IMHO, that is not necessarily an immoral thing (companies who hire internally do this sort of this all the time), unless you are choosing someone as a kickback or because it may provide you extra, untowards benefits.

The reason that I posted this question is that at least in a couple of occasions where my application was "referred" to the hiring official I contacted friends at the agency to find out about the vacancy. In both occasions including one at a U.S. Embassy abroad my friends came back and told me that the position had already selected someone and that they knew the name of the person even before the end of the vacancy announcement.

I didn't think this was a secret. "cherry Picking' resume's is easy and done all the time. Its all about who you know. ie Bob knows a GS-12 slot babysitting unicorns and pots of gold is about to open up. Bob already babysits the T-rex and knows his buddy Steve needs a job. Bob tells steve to drop a resume and the day the job opens up online. Bob has already talked to Maggy (who he is dating) to pick Steve's application over all others.

I have worked a LOT with GS civ's and almost always the jobs are filled before they are announced.

Sure it happens, and in some cases it should. The best person on paper is not always the best person for a team. You can have a great resume and be a terrible fit for the organization, potentially damaging everyone's productivity.

Yeah it happens. Not just GS, this is done in some guard units. I applied for a guard flying slot in my local area. I thought I had the job initially, because I was the only one to apply and the job application acceptance time had expired. Then out of the blue when I showed up for the interview, wallah a new candidate was there. He just happened to be pilot training buds with the chief pilot. I knew before the interview started that I did not have the job.

I don't think its rigged. But CS does look at the veteran pool as well as in service transfers, and promotion with CS, usually they have the preference.

"I'm shocked, shocked to find that gambling is going on in here!"
(Captain Renault in the scene from Casablanca when he shuts down Rick's)
That's how surprised I'd be.

Every employer has a preference to go with the evil they know over the one they don't. Internal placements have been preferred is every office I worked in. However, in most cases that is not an absolute. I am in my 4th position as a civil servant and have not known the hiring officials prior to the interviews. I threw my resume in the hat they called, I interviewed and I got it. I have seen instances where the hiring officials have stacked the deck heavily in one person's favor. It's not uncommon but it isn't the norm either (at least in the 4 offices I worked). 90% of the time it comes down to how well you make your resume fit the job announcement and questionnaire. The hiring matrixes most of the time are how they decide. Tally up the points whoever has the most gets it (in theory lol).

One more reason that many of our government functions are distrusted by the general populace. We see what looks like shady behavior, and there is no transparency during or after the fact. Back to a very old philosophical question. Who watches the watchers?