I brought it up two posts ahead of you.Page 3 and still no mention of catios? These are fairly common in the PNW - not entirely sure why.
https://i5.walmartimages.com/seo/Pa...peg?odnHeight=2000&odnWidth=2000&odnBg=FFFFFF
They put one of these in our local animal shelter, attached to a communal indoor area for the more social cats that were up for adoption. Cats were mostly using the indoor area. Just a small sampling.
I didn't build one because of concern of some of the outdoor cats around us getting to my cats.
. As a kid, our cats were indoor/outdoor, but that changed when I grew up and had my own place to live. Our 4th guy, MeowMix, showed up on our patio emaciated, raggedy, and covered in scabs. While one of our boys has gotten out a couple of times only to realize his grave error, I am sure the outdoor life is MeowMix's strong preference. Well, too bad, buddy! When he started scratching at the window screens in an effort to sneak out, some of the windows are now pretty much never opened any more, and our bedroom window has a baby gate. It's pretty funny to walk up to our place to see him sitting at the window looking like a jail bird
There have been a couple of people I know who had lost cats. I would have tried to offer him to them since we kind of considered him a long-term foster, but they were people who did not keep their pets indoors exclusively. So yeah, we have 4 cats now. 
it is very sad so the cats would be indoors or leashed, same goes for a dog or a rabbit and anything else that could be food for a coyote.