Exactly. Cats should be kept inside at all times. The amount of native wildlife they kill each year is sickening. Some speecies are near wiped out because idiots let their cats roam around killing countless things every day. Cats in australia, for example, kill 10+ billion native animals every year. We have things endangered because of it. We have to have islands and such with no cats just to bring levels up for species.
All cats belong inside, or in a cat run, that cannot in any way cause harm to any other animal that doesn’t stray in to its run. My cat is inside only, never outside without a lead and lives a perfectly fine life. No feline aids, no ticks, no fights, no stray bastards born. Does not contribute at all to the needless slaughter of native animals.
If your cat isn’t tagged so it can be returned to you, and you fined. And they have no way of knowing who that animal belongs to, if it carries any disease, how many animals it has killed, has it littered any bastards. Then yes, it should be put down.
The only problem there will be, would be you would be down one cat, sad for a while and likely get a new one.
Be a good owner, don’t let the cat escape, and there won’t be any ‘problems’
:)