another answer is be enjoyable this was an answer on apex:)
be humorous
Be enjoyable
Me
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.
mobs
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'.
That they invade public space. (Apex)
Mobs are enemies, so I suppose that there wouldn't have been.
No, mobs will not spawn in water or ontop of half slabs.
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.