Today was the first day that a complete stranger came up to me and asked if she could touch my belly. (Hey, at least she asked first!) I should probably qualify the "complete stranger" part. The person and I had been in the same 6-hour training session, and this was towards the end of the session. Still, there were 30 other people there, and I didn't even know her name or specific work affiliation, so I think it still qualifies as "first belly rub from a stranger." It's only been pretty recent that the belly has been really asserting itself in a way that attracts this sort of attention.
I think it would be fun to go into Lucydog mode when people touch my belly...I could lie on my back, with my tongue sticking out to the side, and wag my tail profusely. Oh wait, I don't have a tail...and it would probably be hard to get back up.