Similar here Skol. When I lock it up outside a cafe for eg. I always put it into the highest gear possible (52/11 on mine). All but impossible to get moving in that gear and I'm guessing someone who nicks it probably doesn't know how to use the shifters
Slightly off-topic, I tried a similar trick with my Brompton in Condor Cycles. I left the main hinge undone. My personal best for cycling with the main hinge undone is 5m.