Hi, I have three cats (one the mother, two her babies) very accustomed to go outside home at least a couple times during the day, the neighborhood is very safe for them to do it so, but recently they started pooing and peeing at my very nice neighbors house, specificly in the sand part of a play ground that my neighbors accoinditionated for their kid...so you can imagine how they feel with the situation, the point is that every time a let my cats go outside, the first thing they do is to go to my neighbors's sand and poo....I have been watching them and it seems for them is a neccesity. What I do now is not to let them go outside, and they just are very unhappy, kittys follow me wherever I go and cry and cry....I don't want to have them forever completly indoors knowing how much they enjoy having at least a couple hours taking the sun outside, but neither I want to disturb my neighbors with another "accident" from my cats....I do have a fance surrounding the small backyard of my house, by kittys figure out how to climb it very easy....If somebody knows what to do in this case please, please give me an advise.