The exact spot stays with the people who join
The pin on the public map is approximate. You see the exact spot only after you join. You can report someone, and you can block them.
iOS app in development
People post meetups on a map so others can see what they are doing.
Coming soon to iPhone
RollThru is an iOS app in development. It is not on the App Store yet. You drop a pin for a set amount of time and name the activity. A board game, frisbee, Magic: The Gathering at a bar, or anything else.
People nearby see the pin at an approximate location. They say they are coming in a group thread, and they head there. The pin expires on its own.
Put a meetup on the map for a limited time and name the activity.
The public map shows an approximate location, not the exact spot.
Say you are coming. The group thread is where that meetup talks.
Head to the meetup. When the time is up, the pin expires.
The pin on the public map is approximate. You see the exact spot only after you join. You can report someone, and you can block them.