it's possible to board ships in OFP... if they arn't moveing and are the type that let you walk around on the deck of... the problem is it's very difficult and not terribly practical.
But what I was thinking is a mission in which you have to fend off pirates before they get close enough to board... if they get too close, or cut of the escape rout of the ship that your defending, the mission is failed.
As for smugglers you dont really have to worry to much about boarding the ship than you do just chasing the damn thing down. After you finally manage to stop the damn thing, there could be a movie of you boarding it and arresting the crew.
Anyway, the whole point im trying to make here is there isn't much point in having a USGC pack if there's nothing to go aggainst it.