you can set no go zones inside the GPS fences now. That is a relatively new feature.We had three german shepards when we started (one got old and died). 2.5 acres. Invisible Fence brand. Laci, the mom learned very quickly and had never been am issue. Remington, her son is my constant companion and shadow if I am home. He needed the installers to set it to the highest setting. He is usally very good about the line. Biggest issue is if I go to a neighbors and he thinks he has been away form me too long he powers throught the hit just to be next to me. We did look at the GPS/GEO/Sattelite style but we have a pond and were told those recievers were not waterproof not not an option for us.