One of the many positive things about the 6D is that the shutter is remarkably quieter than the 7D's. With Live View and Quiet Mode, it's as close to silent as it will get with a DSLR, I believe.

I found out later that the group that puts on the lectures at the Tower usually bans photography due to flashes and the noise. It was very quiet except for the speaker, so the clacking of the 7D's shutter was noticeable. I wasn't shooting continuous or using a flash, but I did take quiet a few shots to make sure I got some keepers. I guess if I'm in that situation again, I'll a) use the 6D in Live View Quiet Mode, b) take fewer shots, and c) try to move around more so I'm not annoying the same people.

As far as the restaurant story, the first thing I thought was that picture taking seems to be far less of an issue to me than unruly children and/or cell phone conversations.