While unfortunate that the GTN is so easily removable, is is serialized and more difficult for a thief to sell. You will find that most builders have decided that a thief breaking a canopy is a more major problem than the theft. Most do not lock and I always keep a cover on during away trips.get a canopy cover..... out of sight out of mind - build a lock into the cover....
This. I'd much rather make an insurance claim for some easily-replaceable, drop-in avionics and not have to also build a new canopy/frame/skirts, match paint, etc.You will find that most builders have decided that a thief breaking a canopy is a more major problem than the theft.