Have you ever rejected a candidate in an HR round after they have cleared all of their technical interviews?

If their compensation demands are clearly out of whack, or if they wanted additional things I simply couldn’t give them, like a large initial vacation balance instead of unpaid time off for an already scheduled vacation, or demanded ridiculous moving expenses, a “company car”, etc..

Yes, of course.

Sometimes they fail out due to a background check. Maybe they are a pedophile who wants to work at a daycare (never had that one), or a convicted embezzler who wants to work in your accounting department (I’ve actually seen that one), or a computer criminal who wants to be a programmer or in your IT department (seen that one, too). Had someone lie about a degree (once) and a state license (twice).

Probably it’s not a background check issue.

Mostly it’s over compensation.

If their compensation demands are clearly out of whack, or if they wanted additional things I simply couldn’t give them, like a large initial vacation balance instead of unpaid time off for an already scheduled vacation, or demanded ridiculous moving expenses, a “company car”, etc..

There are people you will move on those things for, and there are people you won’t, and a lot of people in the second category think they should be in the first (but they really shouldn’t be).