irresponsible cat owners make me mad. I own 40 cats and not one of them runs free they have a huge cat proof yard to run in. I have heard of the citrus as a deterent so give it a go. the only other thing is educating people to look after their cats and do the right thing by them, by letting them run loose they are not caring for the cats as they can get into fights and pick up all sorts of illnesses or have unwanted kittens then they have huge vet bills and put the cat down. AND they say they "love" their cats. HUH they don't know what love means