Well, since live performance is a better way to make money these days than selling recorded media, I suppose that one can seriously augment one's income at a gig by flogging the baseball hats, teeshirts, christmas tree ornaments, and signed vibrators. Kind of annoying, though, if you're the talent. I mean, isn't that what a girlfriend is for? - flogging CDs out of a suitcase at half time...
I mean, I imagine you can just *predict* the banality of most lobby conversations.
"Hey, great performance!"
"Thanks."
"Where you playing next?"
"Seattle."
"Really? Wow, that's so cool. Hey, can you sign my CD?"