I believe they will be discharged, lose their pensions and do a couple of years each in the clink.
I doubt that these four were running the show though, I'd imagine HMRC are closing in on others who think they got away with it, shame they can't get the ringleaders.... or maybe they will!
These individuals do not represent the wider RAF and at a time when the public are showing appreciation for all the hard work overseas, the actions of a few can damage the reputation of us all!
Those who are involved but haven't yet been caught, best watch out, because I know many, many servicemen and women are outraged by this and would gladly tip the wink to Customs if given the opportunity!