Law Professor Ann Althouse had what I thought was a good post on the Beer Fest on the White House lawn. On the other hand, she got a lot of push-back on this in the comments.
My number one take-away on this is that one should always be polite to people in power, be they professors or police officers. If they get out of line, bide your time and then use the power of the system to get them back in line. Remember, your grade or your life could be on the line.
Regards — Cliff
PS: And why was Vice President Biden there?