Another thought--since many people don't actually use their garages to park their cars, they don't actually need to open the door often, particularly from the outside. In that case, some garage doors have a built in lock that you engage from the inside. Mine has a spring-loaded bolt that you can use to block the track that the door slides up and down on. Press a lever on the lock and the bolt springs out of the way.

Or there may be a spot on the track you could use a long shackle padlock to prevent the door from moving up, even if the emergency release were pulled from the outside--although this would be even more of a safety hazard than using a ziptie to keep the emergency release closed.