We have the same problem at our ranch. But with it in the middle of the city and surrounded by shopping centers it is hard to keep people out,. We have a NO Trespassing sign on the gate but I have caught a mother ( not very bright) bring her kid and a baby in a stroller onto the ranch so they can pet the horses. I have warned her multiple times that the horses are not all friendly ( they are but they can get riled up and hurt or knock a kid or the stroller over) And tell them they are at their own risk. I have caught this woman on more then one occasion. There isn't really anymore that I could do other then call the Police but they wont do anything anyways.