Filing you in public is not a violation of your privacy especially in a limited scope like a single club. That's not at all equivalent to saying I should be able to read your emails.
Public safety needs to be weighed against civil rights. I don't think women should be drugged because of a extreme fundamentalist a paranoid interpretation of privacy rights.
Also people want to club where it's happening. Even if a club has a lot of people they could still not be dancing.