Be enjoyable
be humorous
Me
another answer is be enjoyable this was an answer on apex:)
you cannot solve the prob. people are going to do what they want. flash mobs are oraganized and unexpected, so unless you intercept some of the planning, you cannot stop a flash mob.
Unscrewed with Martin Sargent - 2003 Flash Mobs UFO Watchtower Dark Tip Total PC Destruction 1-50 was released on: USA: 23 September 2003
Flash mobs are an interesting way to gather people for a celebration, to share the team's win of the pennant with a large group.
Most phrases can be understood by thinking about what each word means. Flash means fast! abrupt! quick! Mob is a crowd, often unruly. Action means to do. A "flash mob action" means a crowd that assembles quickly to do some intended act. However, most "flash mobs" do not act unruly; instead, they orchestrate and choreograph their 'doings'.
Flash mobs are relatively rare in New York City, but they do occur from time to time, often organized for special events, promotions, or social causes. While they gained popularity in the early 2000s, their frequency has decreased in recent years. When they do happen, they can attract considerable attention and participation, showcasing the city's vibrant culture. Overall, they remain a unique and sporadic phenomenon in NYC's bustling environment.
mobs
That they invade public space. (Apex)
Groups of people usually college dance teams, or organizations rehearse and then "randomly" meet at a predetermined location and time and start doing their routine. It's usually to support their cause.
Passive mobs need light to spawn, and they only spawn on grass. If the aggressive mobs are spawning, then it must be night and the passive mobs will only spawn near torches, pumpkins, glowstone, etc. However, Notch MAY have fixed this in 1.6, but I'm not sure.