He doesn't actually want police officers to go on strike! That would be a crazy suggestion! Especially coming from a mayor who relies on the country's largest police force to keep his city from devolving into a cesspool of crime and chaos like that scene in The Dark Knight Rises where [SPOILER] the police were all trapped underground and people started looting the homes of wealthy people like Michael Bloomberg!
"I didn’t mean literally go on strike," Bloomberg told reporters today. "In fact, in New York, they can’t go on strike. There’s a law against it." Incidentally, the law prohibits certain public figures encouraging police officers to go on strike, too.