[Cyclopath]

https://www.vice.com/en/article/pkadqy/hackers-can-remotely-open-smart-garage-doors-across-the-world-simpaltek

[cdestroyer]

many years ago the new cordless phone operatet on the same frequency as garage door openers, drive around the neighbor activating your cordless phone to open

[Anne Elk]

On the low-tech end, my garage door spontaneously opened on two occasions. It's 70's era equipment (if not 60's) and opens either via a battery-operated hand device or the "doorbell" that's hardwired inside, near the garage's back door. I figured it was on the same radio frequency as a nearby neighbor's wireless printer (or some such). I disconnected the plug from the door mechanism, and keep it that way until I need to get stuff in and out. Have never parked my car in there.