Guard shack at the gate and the threat of beatings don’t count?
If someone were physically restrained and threatened from leaving the FLDS facility, that is coercion. The problem is, as with the Moonies, the Branch Davidians, the Jim Jones cult, etc., it is up to the person whose right to travel and associate as he chooses is violated to make the complaint. Alternatively, if an outsider has actual evidence of this sort of thing going on, they have a duty to report it to the local authorities.