Again I don't think this is about authority as much as it's about alignment with the perceived norm. People in positions of authority usually claim that they're merely upholding normal, necessary or desirable values, and others try to align themselves with that - often even without any explicit coercion, and especially if the authority is perceived to be of a higher social status.
One of the key things from milgrim's experiment was the notion of giving up responsibility, the "teachers"in the experiment were absolved of all responsibility by the experimenters (authority). I would expect the same dynamic in crowds. Some people seem to feel that they cannot be held responsible for their behavior when they are in a crowd -- and to a large extent they are right. Before modern technology it'd be hard to keep track of who did what and when.
Note: It's hard to take "studies" like this seriously, if you've ever read milgrim's book it's amazing the length they went to try and verify their results; whereas nowadays studies seem to be a lot less rigorous.
Although I havn't seen the show, I doubt that it could be considered a scientific experiment. At best it highlights the Milgram result to a modern audience who may not be aware of it. Experiments like Milgram's would be unlikely to get past any ethics committee these days, due to the potential psychological trauma caused to participants.
