My past wedding I have to say has been my best experience with guests ever. They were EXTREMELY respectful of me and did everything they could to let me do my job and not get in the way.
First dance, for instance, everyone wants their shot, but every single guest stood back and watch me and waiting until I stepped back and took my camera down and then put up their cameras to get their shot. They were on the opposite side of the dance floor but one guest later said that she knows how much wedding photographers hate it when guest's flashes get in the way. It was so nice to hear that someone was aware and conscious of it!
Probably far fetched to hope this is becoming common knowledge and will be a new guest trend, but it was nice to get that respect from these guests. And reflecting back I realized I haven't had an Uncle Bob issue at any of my 2012 weddings. Maybe people are really starting to realize that they don't need to take a million pictures that they will probably never look at again at each wedding they go to. We can only hope!