This is the SLAMMER! To lock up the ruthless criminals under bar, lock, and key.
My idea for implementation:
You get teleported into the jail(or just drive in the teeny back door).
A WW thief gets rid of your current flag.
You are forced to pickup the Obsesity flag in the jail and therefore can't get out of the small door.
To simulate 3 turns - destroy 3 tanks and you lose the obesity flag.
Drive out the back door if you want.
Because of all the times a single player might have to keep getting in there. Think, you said by teleporting. Most people don't know where a tele will take them, unless it's clearly marked.
If there are 50 obesity flags on the ground that people are forced to pick up, when a person is done with his 3 turns and can escape, how do you prevent him from picking up another obesity flag?
Also, what if thief steals someone's obesity flag while he's in the jail?