I think check swings are probably 50/50, umpires kinda have to guess if it's close. Replays show its nearly impossible to truly hold up once the bat leaves your shoulder
I kinda feel bad for her tbh, I hope this was her dream (to make the majors) and not forced on her by the league. Anyway hope she does well - umpires just like players/prospects spend quite along time working their way up through the lower levels.
I don't think this is on Schneider at all in fact I thought he did a great job managing the pen this game. Bringing in Varland and going with high leverage relievers was a great move