As many of you know, Geocaching.com has made changes to their event guidelines (Feb 2015) so that now all events must last a minimum of 30 minutes.
Here is what we suggest for the WWFM events:
You can meet early at a certain location, and make plans together for the "Flash Mob" portion of the event at a nearby location, and then meet again at the first location after the flash mob is over.
Another idea is to start the event with the "Flash Mob", and then have everyone meet at a second location to continue socializing. The event host must be present for 30 minutes, but you can also have a longer event.
The fun of the "Flash Mob" part is to do something unique, different, entertaining, unusual, etc. so that people (muggles) nearby are surprised or amused! It works best to keep this portion short.