My sister reported the cat not eating and puking what she did eat, but at least over her first night back home her diet is back to normal so I think she was just trying a hunger strike in hopes that I would get back from vacation early. Will still keep an eye on that to see if there's something more serious going on, but her other behaviors are also back to normal so far.
The other trick the cat tried was seeing if she could get back in her travel box and if that would summon me.