So in one word, If you don't cooperate, your presence in Liberty is illegal, you must stay dock or leave, if you don't...we will destroy your ship... , And as you may have seen getting registered is extremely easy,
You just have to respect the autority, obey to the orders, and do a little RP post on the forum. This way, OORPer will have to go on the forum if they don't want to have the Goliath or the Athabaskan on their asses.
( Sorry for all the OOC in my 2nd link, Going to do a cleanup in a few minutes)