I don't personally know of any pet hoarders, no... but I keep seeing news articles of people being warned, and sometimes even arrested for having too many animals in the house or on their property. While I understand the love of pets and wanting to "help" every animal that seems to need help, there's a definite line that shouldn't be crossed and I think the hoarders cross it. Not sure where that line is, but I'd think that once it becomes a difficulty to pay for their food and vet care would be a pretty good indicator of where the line is. Like others have said here, there's a point where doing things like this ends up hurting the animals instead of helping them which was the original intention.