I like the general Idea of joining a NPC faction, in this case the pirates, and gaining some reward for some penalty (not attacked by pirate-stations, but by all other factions ), but there should also be a automated way of getting fired - Like shooting down a faction mate, otherwise you could abuse the system easily: Joining the pirates and raiding them without getting counter-attacked etc (i think for the "shooting at" version there is even a faction option to activate for
Valck 's way of doing an improvised version for now).
The most intressting part about joining another npc-faction is the possibility for a "nomad" kind of style where you could use the pirate-stations for a home (or thinking further the trading station for another npc faction example) and still be without a "real" home.
Could also come in handy for starting players, to join such a faction.
Not joining and still be friendly could be achieved by paying the regular "insurance".