Neighbour's Remote Operating Your Garage?

Very unlikely but can happen where your neighbour's remote can mistakenly operate your garage.

Why does it happen?

The only way this can happen is if your neighbour has the exact same model and brand motor as you have in your home and during the programming of your remotes (the first time your remotes were programmed to your garage motor), your motor is put into learning mode and ready to accept a new remote, your neighbour was within range and using their remote to open their garage. This would inadvertently program their remote to your motor.

How to stop your neighbour's remote from operating your motor? 

The only way to stop this from happening is to erase your garage motor memory. Which will remove both your's and your neighbour's remotes from your motor. Then you must recode all of your remotes back into your motor. It is best to consult your motor manual on the process to erase the memory and recode your remotes.