I live in a neighborhood with so many outdoor cats. They will fight in our front yard at night. They will sneak onto our back porch. We have a dog who hates cats. He has actively chased them from our yard, and if a time ever came when he happened to catch up to one, it would be a bloodbath.
Our neighborhood is near a field that happens to be home to at least one coyote. I have seen that coyote wander down the road and people have even spotted it in fenced backyards before. I'm sure one reason it dares to wander into backyards is because it knows there are cats wandering freely around here.
The red tailed hawks in the area may not be large enough to carry off most full grown cats, but that doesn't mean they won't try.
Raccoons aren't exactly nice to cats either.
And i can easily point out several houses, including my own, with flowering plants out front that could absolutely make a cat sick or worse. Lilies, for example.
Even before tackling the problems of cars, malicious people, poison from pest control, or the ecological damage cats themselves cause, just the fact that other people will decorate their own yards with plants that can poison a cat should be enough of a reason to keep them inside!
Hell, just the fact that you don't know what they're doing or when they'll be back should discourage you from letting a cat wander outdoors! Anything could happen out there! You don't know what they're eating, you don't know what injuries they might get, what diseases they could come home with, or anything. That's scary! Just keep them inside!
