I've had this happen to me as an independant. Gate camping, and by Bounty Hunters "in the pay of " the LSF or Navy or whoever they want to hide behind as well as the "official" navy.
Sadly, there's a rationalization behind it, something these people can use to sleep at night. Instead of patrolling like their NPC counterparts, they'll be "border patrol" or crap like that.
As for Corsairs in Liberty. You're right, there are no NPC's there, does that mean that Corsair Smugglers won't try and get into the most lucrative market?