The rational thing to do in a situation such as the Vegas run is to profit from it.
Henceforth, on all flights where Virgin deems there to be excessive drinking, leading or not to verbal and/or physical abuse of other passengers, drinks in all economy cabins will be subject to the following charge scale: small beer - 8 pounds; small wine - 10 pounds; small spirit bottle - 12 pounds. All drinks must be pre-ordered and pre-paid - there will be a single serving run. Only cash will be accepted, and only in the right change. EG - if all you have is a fiver, and two two-pound coins, no dice. Can't buy anything, tips not accepted, nor are overages.
All alcoholic duty free purchases will be stowed in overhead lockers with locks, which the cabin crew will secure prior to departure, and re-open 10 minutes before landing.
Any passenger visibly subjected to verbal or physical abuse in the judgment of cabin crew will receive a 25 pound voucher to be used on future Virgin flights.
The policy will remain in force for the minimum of one year, or until one year has elapsed from the latest report of drunken behavior.
Anyone wealthy enough to be able to afford UC will not of course be subject to this policy; that wouldn't be cricket. The situation with PE will be monitored after the policy is enforced in Economy, and if problems should arise in that cabin, it will also be subject to the new drinks policy.
You'll either be able to eliminate fuel surcharges from the Vegas run (to be replaced by a much more profitable type of fuel surcharge in the long run), or you will get rid of the drinking problem on the route, and save/make some money.
I'm sure with the kind of actuarial sophistication they have in the industry Virgin should be able to determine the right price point and pricing policy for the booze to achieve whatever outcome they desire. And, yes, of course you'll have the usual litany of complaints about how only rich people get to have fun, and how we're setting a policy for a few bad apples to the detriment of the majority, but, you know, that's tough. We're in a free market, and what counts is money. I mean, sixty years ago, the kinds of people getting rotten drunk in smelly bars in the nether regions of the old country wouldn't have gotten within 5000 miles of Vegas, so what do they want now, free booze? [;)]