Happened to a Norton in the garage just when we were changing to BMW's. But that would have been a bobby who wanted a new bike....so doesn't apply to real life.......
Why anyone would wreck a Norton in order to get an R80/7 is beyond me?
If it serves the purpose of giving you confidence and piece of mind why not fit one? It is a visual deterrent even if it can be forced off. Its certainly no worse than some of the junk people fit to their GS bikes.
I have classic bikes and they are not fitted with locking petrol caps, I have never had problems but people still fit locking fuel caps. Up to choice... yours.
Noticed you were asking if anyone had one, not, are they any good.
imo, no one notices its the filler cap unless theres a lock on it,
only other bm riders usually know its there , most people wouldnt have a clue.
like most of the touratwot stuff, its just good marketing to get you to buy something unnecessary and overpriced