we live across from a "snooper

The first house we bought as a young couple (1974) the next door neighbors were so pushy they would cut across our backyard, right under our kitchen window, as a shortcut to the next street. One day I was feeding my son in the den (a back room on the first floor) and that neighbor appeared in the doorway. She had let herself in the back door, walked through the kitchen and down a long hallway to get to the den.

We had little money in those days. We'd spent it all on the house. Somehow we found enough to put a locking gate around the backyard. End of our problem.

Some people just need boundaries. Good luck with the snooper :)