Proof, as in video camera proof? No. I don't have that. But I would say that the other umpire approaching me after the game is rather compelling evidence. I didn't argue or complain during the game, because whenever I've seen that happen the strike zone gets smaller for the complainant. The only comments I made to her were questions, and was about two pitches, asking where it was/why it was called a ball. Who knows, maybe my catcher was saying stuff I couldn't hear.
Maybe the other umpire was trying to smooth things over. Maybe the other umpire has got it in for her. Maybe the other umpire... who knows?
If all she's doing is calling balls/strikes without any other commentary, you've got no justification for calling her biased. All you've got is a gut feeling.
Has she ever called your games before? If not, why would she even have it in for you? She's got no history with you or your team.
I've never whined about it, and can't recall ever telling an umpire their zone is wrong, or too small, or whatever. I will ask why/where it was that it was called a ball. All I want is consistency between the two teams. In this case it was obviously bad enough her partner sought me out after the game to apologize. It's got to be pretty bad when that happens.
Never said you were whining, just saying that we get a lot of whining!