The shoulder strap.
So there I was in a place with very few folks (like, almost nobody) around, minding my own business, concentrating on my subjects when this junkie-looking person emerges from nowhere, walks up and mumbles in my ear "The seven dee...", and engages in conversation. For a few seconds I wasn't sure whether to run away or use my "seven dee" for a pre-emptive attack, until I realized he had a Sony DSLR strapped to his hand (maybe pre-empting a pre-emptive attack from a Canonite...), and figured out he had recognised the writings on my shoulder strap...
After a bit of chatting I have to admit he sounded like a "true photographer" and of course he looked the part of a true artist, in stark contrast to me, "Mr IT Support" out on a jolly with my 7D inbetween rainfalls... Unfortunately he was too busy to harrass me for too long (or probably I was too uninteresting to talk to...)
So the 7D shoulder strap could have landed me in deep trouble: I can imagine the local headlines "mad foreign photographer bashes in the skull of established local artist, claims self-defence!" or something like that, and the subsequent threads here and on the Canon and Sony forums on dpreview. Ouch...
7D and 60D, Sigma 12-24, Canons 24-105L, 100-400L, 50mm f1.4, 100mm Macro. 580EXII, Elinchrom Skyports, Eye-Fi, Apple Macs, iPhone 3GS, PS4, LR3. Socks and jeans with holes repaired.