Definition - What does Unlawful Assembly mean?
Unlawful Assembly, very generally speaking, refers to a group of people who congregate for the sole purpose of breaking the law and/or disturbing the peace. Various countries treat unlawful assembly differently, but the consensus among these jurisdictions is that it is very difficult to be found guilty of unlawful assembly.
Justipedia explains Unlawful Assembly
In the United States, the First Amendment of the United States Constitution provides that "congress shall make no law . . . [abridging] the right of the people peacefully to assemble . . . ." So, the act of a group of people assembling in order to discuss different matters has always been highly protected by the United States Supreme Court. As a result, it is very unlikely that a group of people congregating in the United States will be found guilty of unlawful assembly unless the group is clearly plotting to break the law in some fashion.