Relatively rare... such an occurrence as mentioned by Nikumba.
Cats are outdoor animals... even the "domesticated" ones... mine get so upset when they can't go out for a few days... as have others we've had in the past, it's like night and day in their behaviour, you can clearly see the unhappiness of being stuck inside.
I would not like to keep them locked inside based on my own fears of what might happen to them, leading to them living an less happy life simply because I'm scared of what someone else might do to them. That's incredibly selfish... they are living animals too, you know...
Say it was as simple as this... given the choice... would you rather live:
- a short & happy life
- a long & unhappy life
??
To be blunt, I would say you don't know what their best interests are, you are only really considering yours... not meant as an attack by any means, only a statement of my interpretation.
I won't judge you for it, there is no benefit in it & I completely understand your viewpoint... I was destroyed inside when one of my little ones was run over by a car... it felt like i lost a child and i still haven't fully recovered from it. But he was so excited to go outside that day, I'd make the same choice to let him out, safe in the knowledge that that's what he wanted, rather than me trying to overly-protect him.
Silly little bugger had no sense of direction, what-so-ever... he used to jump over a couple of fences and get lost, he'd head on in to a neighbour's house, curl up on the sofa - and they'd call us or bring him back a few hours later lol... must've been at least 4 different neighbours in his short 6-9 months at that house!