Nah, not mischievous kids. Finally found the (duh) operating instructions. Our wireless door chimes provide a choice of six sounds (three chimes and three song snippets).
When the phantom rings, it's a brief hodgepodge of sounds, not any of the six selections. Apparent problem is the 150-foot operating range, far enough to include the street and vehicle traffic, the likely culprit.
This version unfortunately has a crude frequency adjustment. Five wires, cut any or some of them to change frequency. Not too bad a chore for either of the indoor receivers, but have to cut the same wire(s) in the front door transmitter that is tinier and has been painted of course to match the door. Not going to mess with that until the weather warms up.