No, this isn't about rubbing up against people on the subway. I came across the link to this story on another blog I read and I thought it was not only compelling photography, but also an interesting interview. Go read the interview and look at the guy's website if you're so inclined. The interview has some of the best photos, but I think they're all pretty neat.
A Conversation with Richard Renaldi about 'Touching Strangers' (Conscientious)
Link to the photographer's site aimed at all of the photos he's put up from this project:
Renaldi - Photographs
Now that you've at least skimmed the interview (if you didn't, go back and do so or give up on the thread altogether), would you pose for such a photo? He's going to pick who you pose with, and how. We're presuming the guy doing the picture taking looks like he's legit and has a copy of his book handy, etc. I'd find this a hard sell, personally. Having seen his site, I get it now and if I had turned him down, I'd wish I hadn't, even though I generally don't like having my picture taken.