It's a good point, but some animals would of been kept purely as caged animals, especially as many owners would of lost their nerve as the cats got older.I've been in contact with a 3/4 grown cheetah that was hand reared, but still very unpredictable & scary at that age! Haha....So I can imagine many owners cutting contact early on.
Why is it always a Cougar or a Panther, why never Lion or Tiger? I'll take a wild guess that Lions & Tigers would find it a lot more difficult to go unnoticed, I'll also take a wild guess that not many people were irresponsible enough to release a lion!?!?