if the main account can be traced down with no doubts i'd suggest: halfing xp / gold / crafting xp selling all mats and ships @port royal (yes i'm british and i was waiting for the PB as the incident happened)
a full reset and/or ban is too much i think, those actions show that exploiting will be punished and will hurt the player very much, but not to a point where he/she stops playing. after all this is a game, and yes exploiting is no joke, but the player should not be forced into starting from the scratch again.