cats

Well you might have heard of cars, highways and other such human created things that haven't existed during all that time.

Here's one study where they examined the welfare concerns over unrestricted/unsupervised outdoor access (and other concerns). https://pmc.ncbi.nlm.nih.gov/articles/PMC7070728/#sec5-animals-10-00258

Also how are you mitigating the risk of “such dangers” for pets and children?

I wouldn't allow a cat or a small child to roam around unrestricted. It just seems due to the inherent threats pretty irresponsible.