I have always been a supporter of letting the cats out of the house as I think that they can go crazy. Funnily the 2 cats I lost to accidents weren't caused by the classic car accident. One was killed by my neighbour's car (he used to love sitting under neighbour's car and the neighbour, I suspect did it on purpose as he is an alert cat and the neighbour, well, he is the type who would keep pictures of his fav celeb under the stairs if you know what I mean). The second one was not killed by a car but I suspect a cat killer (refer to early posts for story) and body dumped in front of my house. If you're really afraid of kitty being killed, please keep him at home because there is no guarantee that he won't be killed by other factors as well (accidental poisoning, cat-hating neighbours). I have a neighbour who gave her cat away to her daughter who lives in an apartment because it was allergic to grass. It is happy to live there. My 10 sens' worth - desex them, they won't have a tendency of disappearing. From experiene, i find that (even desexed) female cats tend to be homelier and males tend to run out (naughty boy syndrome)