This is Obnoxious, Right?

So, some of the neighborhood kids use our backyard as a cut-through from the school bus stop to neighborhoods...somewhere on the other side of our house. No biggie. I don't love it, but I can live with it. Until we moved in last year, our house was the 'lemon' in the neighborhood, and sat vacant for months and the backyard is still a disaster, so I could see why it is the obvious choice for a shortcut.

Well, this morning, I looked out the kitchen window and saw, not only a kid cutting through, but HIS MOTHER was with him. And then, five minutes later, after the bus picked up the waiting lot, the mother walked back through our yard. Tell me I'm not overreacting...that is totally inappropriate, right? An adult should have enough common sense and courtesy to not walk through other people's property...shouldn't they?

Also, as an aside...anyone have suggestions for preventing kids from walking through the yard? As I said, I don't care much right now, but we're going to be leveling and seeding the yard, and footsteps will not be welcome then. No budget (or desire) for a fence. Thoughts?