So how do you stop people surrounding you unless you're Jason Statham? It happened to me once in Florence - they didn't get my Leica and didn't seem interested in it, but they did find a couple of hundred bucks in my jeans pocket.
Good point. It happened to me once in Prague while I had stopped on Saint-Nicolas' stairs to cure something on one of my feet. The place was empty but as soon as I rested myself down and took one shoe off, about six or seven young Russians surrounded me - and that was not fun.
I screamed and they left without assaulting me (and my belongings) eventually - much luck for me then.
That was the only time this happened to me, but I learnt the lesson (I'm sure those guys had been following me for a while, just waiting for the good opportunity to try to take my bag off).
Recently in Paris I met a very friendly guy coming from the New Orleans who told me he hadn't dared bringing his Leica M9 with him into France for the fear of being stolen. I told him that this was quite an exaggerated hoax. Fortunately you still can walk in Paris without being stolen (of course don't go to Montmartre inside the young Gypsies crowd with money in your pockets or valuable things around your neck or shoulder).
Quite often, people looking like the perfect rubes get stolen in very touristic places where there is nothing really interesting to see or photograph (because of the excessive touristic aspect of the place)...
As for disguising expensive photo gear into pieces of junk using black masking tape and the like, I'm not convinced at all : thieves do know the trick...
So, yes, the best advice remains : small bag not looking like a photo bag (if possible) ; casual clothes, with no flashy colors ; no backbag ; wrist strap (or neck strap twisted around your wrist) ; walk quickly ; don't stay for too long w/o walking ; never let people coming too close to you and change directions very often.
But there isn't any magic recipe...
Edit : grasp your belongings very firmly and move away PDQ as soon as you meet people :
- coming playing soccer around you
- showing you something they pretend to be funny
- carrying newspapers while being obviously unable to read
- asking you something OT (e.g., you're sitting at a café terrace and some people come by and ask *you* to help them to do something, whatsoever)
Etc.