I've never been to a show where there was booing, although there was one that came close. The 2002 National Thespian Convention, comprised almost entirely of excitable high schoolers, gave instantaneous and thunderous standing O's to every mainstage show except the last one, an execrable production of Blood Brothers. And this was BAD. Easily the worst stage production I've ever seen.
When they dimmed the lights to start act 2, the audience actually protested and they had to bring the lights back up and wait for everyone to shut up. And while the audience was polite enough and eventually gave a standing O at the end, everyone hesitated for a few seconds.
You know a show sucks out loud when a large, easily impressed crowd of your peers doesn't like it.
http://community.livejournal.com/ltd_brands_suck/