A young cat started appearing in our garden during the summer, really friendly boy, loved a bit of fuss - we figured he was a neighbour's cat.
Recently he's started showing up again - he has got really fluffy - at both the front and back doors, meowing pitifully like he's never been fed in his life. I am well aware he may be playing us here! 
We've let him in a couple of times and he's guzzled away on our cats' food, again like he's never been fed in his life.
We really don't want to steal somebody's cat - but we are feeling really sorry for him! I work shifts and have got home at 4am in the last couple of weeks when it's been freezing outside and he's been out there meowing to come in.
He's not microchipped - I've got a scanner.
Last night I popped a collar on him with a message and my phone number - then he turned up again in the afternoon, collar had gone but nobody has called.
If he belongs to anyone I suspect our next door neighbours - not sure if anyone remembers but I posted a thread about their old cat that got stuck in our roof after being run over - they didn't even have a vet for her! They had another cat too that moved in with the lady over the road.
AIBU to keep letting him in for cuddles? Should we keep sticking collars on him with our details in case he somehow wiggled out of the last one?