I would want to look at the collars to make sure they're unlikely to catch on things, and ideally can be pulled off if the cat gets caught on something (they wear breakaway collars now, and rarely remove them).
Something to look into when we have a free minute - and I bet there are bigger pet stores in Seattle than we have around here!
The little bandit guys are cute - but there were two the first time we saw them, and there are three now, and who knows where it will all end! And if they ever did have a disagreement with our cats, it would not be a good thing.
If anyone has any experience using one of the doors with the magnetic or infrared keys, I'd love to hear your opinion.