Problem is skins take up alot of the mission file, therefor creating alot of skins would cramp up and slow down the server once they hit a limit also would make you download a big ass mission file, not really worth it, better with custom vehicle that everyone can use and also looks cool. :)
How about the come in with boats at kavala beach armored vehicles stand there ready and they form a massive convoy up to their area police will chase but not engage, no fights cool looking no problems right?