She was stoic. She complained (she says "no", her meow really does sound like a "nooo") but did not bite or scratch us, but she left as soon as she could.
I want to do it to help get as much loose hair as I can so she does not throw up hairballs, last summer was really bad, she threw up a lot while we were gone. Retrospectively I think she was probably already diabetic and also the sitter we had last year came at very irregular times, and Bella knows how to open the 2-slot feeder we were using, so all that together means that she was probably either starving or way too full, and that was probably the reason. This year will be a lot better.