New idea for Zune,ipod,iphone- Social Cameras!

Here's an idea that came to me while waiting for a train to Genova. I was standing on a platform, across a pair of tracks a man was taking a picture of something in my direction. I was in the picture, the camera seemed to be pointed at me.
I thought to yell my email address across the tracks asking him to send me a copy of the picture. (Assuming he spoke English and I could be heard over the din of the station.)
Then I thought my cell phone or camera could do that for me. It could be beaming my contact info. Then I had a better idea. What if his camera, as it was taking the picture, also broadcast the bits to every other camera in range. My camera, sitting in my napsack would detect a picture being broadcast, and would capture it. (Or my cell phone, or iPod.)
Wouldn't this change tourism in a nice way? Now the pictures we bring home would include pictures of ourselves. Instead of bringing home just pictures that radiate from me, I'd bring home all pictures taken around me while I was traveling.
Of course if you don't want to broadcast pictures you could turn the feature off. Same if you don't want to receive them.
A standard is needed, but the first mover would set it, and there is an incentive to go first because it would be a viral feature. Once you had a Social Camera, you'd want other people to have one. And you'd tell them about it.
Not sure what technology would work best here. Bluetooth isn't fast enough. Is wifi overkill? Maybe a low-power radio transmitter?
When I told this idea to a bunch of friends at breakfast they said they probably already have these cameras in Japan. Do they?