Applause and Embarrassment

Two days ago, I attended a scientific lecture which was open to the public, so there was an audience of a certain kind there, mostly of older, middle-class retirees. The man who introduced the speaker (this was an invited lectureship) walked up to the podium, and as he delivered his opening remarks, a cellphone went off. I think it might have been staged, because he said, snippily, "turn off your effing cell phone!" with a slight hesitation before the key participle of the sentence, to applause from the audience.

My question is: why applaud? There are a few possible reasons:

1. They were glad that it wasn't themselves being rebuked,
   
2. A feeling of self-righteousness, a sense of populist vigilantism - 'finally that guy got what he deserves!' (there's always that guy in every audience),
   
3. Plain schadenfreude at seeing someone else publicly embarrassed,
   
4. Or, a desire to conform with the wishes of and flatter the dominant personality in the room, viz. the person at the podium.
   

In any case, these are not particularly edifying reasons and it hence made me uncomfortable that people are so quick to turn against the nonconformist in their midst, whether for good or bad reasons, when given the appropriate encouragement to do so. I'm flagging this incident in my mind, to remind myself to look out for more on the psychology of crowds.