NBC RIGHT NOW-- Police in Washington State are asking the public to stop tweeting during shootings and manhunts to avoid accidentally telling the bad guys what officers are doing.

The "TweetSmart" campaign began in late July by a coalition of law enforcement agencies. It aims to raise awareness about social media's potential impact on law enforcement activity.

Some have called the effort a step that could lead to censorship; others dismissed it as silly.

A social media expert at the international association of chiefs of police says she's not aware of any social media post that has led to the injury of a police officer, but there have been a few close calls.

Police suggested some dos and don'ts for the use of social media in emergencies like...

- Get to a safe place and call 911 if possible.

- Do feel free to let family and friends know you've reached safety.

- Don't tweet or post about the movements of police, or post pictures of officers.

- Don't endanger yourself to get a picture to post online, no matter how compelling.

Police did say however posting pictures after the fact could help investigators find out what happened during the event.