Then grant the official factions the rights to deal with the independents.
Otherwise they are your problem not ours. The official factions should not be held accountable for the actions of a group of idiots who want to fly battleships all the time. With the new mod and the new IDs that are part of it I feel the problem will be taken care of rather quickly.
As to BH being permitted to interdict smugglers, I suggest you read up on the rules page.
It is in there. BH are permitted to scan for contriband just as any other lawful can. There is no mention of a contract being required to do so.