[OldDeckHand]

Before you laugh, this isn't about the "tween star" Bieber. It's about the question of whether the police have the authority - absent a court order - to compel someone to say something (the something in this instance is a Tweet), or be arrested.

Sure, you can't incite a riot. But, can the police order you to quell a riot? It's an interesting question, and one that has 1st Amendment implications.

[apillar]

The crowd of teenage girls became unruly, and cops told Braun to announce on Twitter that the event was cancelled.

Wouldn't that have just made the crowd of teenage girls ANGRY on top of being unruly. This guy probably was smarter than the police and knew if he texted the message it could start a riot.

[WayneM]

So who stuned Bieber?

[6SJ7]

If cops can compel you to write anything, then it won’t be long until...

I love Big Brother
I love Big Brother
I love Big Brother

[robby]

This is funny. Three year old crying over Justin Bieber.

http://www.youtube.com/watch?v=dTCm8tdHkfI

[DaxtonBrown]

[But, can the police order you to quell a riot?]

Can Jim Robinson be compelled to call off a ‘riotous’ Tea Party event?

[Hebrews 11:6]

If I'm not mistaken, in most jurisdictions it is indeed a crime not to obey a peace officer's lawful order during an emergency. Thus, if a riot is already occurring, does an officer have the right to order a citizen's assistance in a limited way?

You overstate the case. The officer was not asking him to quell a riot, a task which might include physical or even armed intervention. He asked him simply to help discourage a riot by sending a message, in this case electronically.