You're obligated to comply with a lawful order from a police officer. Failing to do so is unlawful. So if the cop says,"tell them to leave [because you've created a dangerous situation by being here]" you'd better comply, or you'll get sent down. Just because they told him to do it with twitter makes no difference.
Wow, what country do you live in? Mine has a constitution with due process protection, freedom of speech, and other useful constraints on government to prevent them from just ordering me to do things like that.