Saw a relevant picture once in a bike mag.
The bike was a customised chopper thing.
When parked it had a two-inch spike that stuck up through the seat.
Nice.
I'm thinking maybe another security device might be a cable that is locked onto your handle-bars. Kind of a bike version of that "club" thing that car drivers put on their steering wheels.
The cable could be long enough to go to the back-end of the bike and back. Put through the pack rack (stop it getting stolen, too) or through the grab rails.
The cables might then make it "hard" for anybody to have a checky sit on your bike.
Dunno.
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