In other words, they are asked to do overtime. So, as long as they are getting adequately paid for that overtime and they are not forced to do so (but I assume you can always find at least two people out of 20 who could do that), I don't think it's a big deal.
That would be my concern. I bet in at least some cases they're told something like be here at 2 AM or don't be here tomorrow.
A better comparison - you're a member of the https://en.wikipedia.org/wiki/Actors%27_Equity_Association, the part which you auditioned for says "dog", and the script & stage directions are within general AEA guidelines for animal parts.
I've only volunteered in museum work - but there are obvious social rules about interacting with wealthy benefactors, and I'd assume that any competent employer in this space is carefully screening for comfort and skill with those rules.
(BTW, "wealthy benefactor" is very much a pay-to-win system, with tier after tier of "just how many $thousands did you graciously gift us with this year?" reward levels.)
If someone is doing it because of the arm twisting done by the economy and personal financial circumstances then of course it will not land well. I will feel exploited.
On the other hand if I am coming from a place of joy to be an usher at an odd midnight hour to a more sic recital, where I am paid peanuts or nothing at all, but I get to see the show and participate in the collective enjoyment of wonder it would land very very differently.
People get paid to sell their organs to tread water, I doubt they feel happy about it.