I have actually been doing follow ups of people who have adopted kittens from us, and so far, only 2 out of the 15 i rang haven't had it done yet - both have said they will have it done, and I will be ringing back up in a few weeks to make sure - I would be surprised if the one I spoke to this week didn't get it done though, with the scare tactics I used. We couldn't keep them all until our vets will do them at 5 months, 4 and 5 month old kittens can already be hard to home, as for some unknown reason, they aren't seen as cute and cuddly as 2-3mo's. Also, we dont have the space, and by keeping them all till that age means that other litters will have to stay on the street, and we can't do that, I would much rather do follow ups to ensure it has been done - we do pay for the neutering of kittens though, they only have to use our vet and show their adoption paper, so it does seem to be working.