Ding Dong Ditch!

Mystery Solved!
Our wireless doorbell stopped working many months ago (now #756 on list of things to attend to). But, strangely enough, it would Ding Dong when no one was at the door. Recently whenever I rushed to see who wasn't there, every time the UPS truck would be driving off, but no fruit of the month club packages were waiting at our stoop. I started thunking- could a neighbors wireless doorbell be somehow in tune with our receiver? Just an hour ago it happened again, and there, the proof right before my eyes, was a solicitor holding a shovel with his mittened thumb firmly jabbing the doorbell 2 doors down.
Wonder if their ringer goes off when I push our doorbell? I'll try tonight at 2am to teach those pests a lesson!