We have 2 lovely one year old cats, both neutered and microchipped males (brothers). They have free access to House and garden, and we have cat flaps for our kitchen and garage. Problem is, next door’s cat keeps using them and eating their food, and they are afraid if it. Are microchip cat flaps reliable? I’m thinking of getting them, but worried in case they don’t work properly and the cats get stuck outside, while we are out!