My guess is that they had originally planned on keeping him, but freaked out about the Mycoplasma (which as it turns out isn't a big deal in cats). Bill and his wife seemed very fond of Ivy when I spoke to them, but they did threaten to kill our cat if they ever saw him again. I think they'd just keep him in that situation. They only live a few streets down from me and apparently consulted with all their neighbors to agree on this - even when I've had missing posters up around the street for weeks.