As long as there are no reasonable limits set on alcohol consumption at the airports by passengers before flying, such incidences will continue to occur. The transformation of airport terminals (after security) into shopping malls and 'pleasure' zones has blurred the edges of what is daily life with the rarified business of aluminium tube conveyancing.
The way I read the report, the limits at the airport (do remember that if you are tanked up at the airport then you are likely to be turned away from the flights. Just because there isn't a set "limit" doesn't mean it's a free for all) wouldn't have made a difference since they got tanked up on the Virgin flight itself.
So maybe it's time for Virgin to review their "free hooch all the way" policy.