You have to be careful with those beware of dog signs. If you want to use one get it in writing from someone what it is for. I had one up on our fence when we had a corner lot. I did alot of work with rescues so never sure of the temperment/stability of the dogs I had in for the first bit...
Video cameras are a wonderful thing. We had to do that two years ago with our neighbours. They would stand at the property line and stare (harass) the dogs in their run till they barked and then call in a noise complaint. After the 5 time, I decided to video tape it from my bedroom window and...