Always open gates and leave them open when dealing with a mark who has a gate. There are lots of fringe benefits to this, For example, his expensive purebred dog might get out and run away. Or, someone or something terrifying could come in. Another benefit of vengeful gatekeeping is that you don’t even have to trespass, Just opening the gate is enough.
When I was a kid, we had a mean old man in the neighborhood. He lived on an estate sitting in the middle of ten acres of woods. We used to open his gate all the time, then go on our way down the road. He’d spend an anxious hour or so hunting for us on his land, never finding us, of course. His own paranoid imagination was our best ally. This concept will work well with doors, too. Think about your mark finding open doors or windows in his house.