The player version of the teleporter gun functions as a ban gun to ward against griefers. It requires three players to shoot a single person "kicking" them out of their current settlement
no settlement to join icon will appear once you have been banned by the player from a settlement
AI Version
AI's teleporter gun is different from the players in that it puts you in a AI Jail. It is only carried by yellow and blue settlement AI because they are the only ones that produce jails.
when Jailed by the AI a settlement to join icon will appear allowing you to rejoin your settlement