The group size thing is of course easily bypass. It was not intended to be a preventive measure, but a reminder from Big brother that we are watching you. People are required to use real name and other personal information to register and law enforcement can freely read those information. It was not unheard that people would raid by police for their online activity.

So, the group size cap is just a rule to say if your group was not over the cap, you will be fine. If you bypass that somehow, you enter a grey area where the government may or may not inference you depending on the nature of the event.