...how many pax would you have to unload if you put a breathalyser at the gate?
Gee that would be nice. Much easier than dragging them kicking and screaming out of the back row on arrival after they've made dicks of themselves for the whole flight.
Gotta say (and feel free to disagree, it's just my experience), the vast majority of disruptive, violent and downright feral pax who I've seen cause problems were either intoxicated/high when boarding, or made themselves that way mid flight, usually by consuming an entire family ration of duty free spirits.
Of course a few unfortunate people are psychotic or deranged and flip out without warning, but I can only recall a handful of them versus a hundred or so drunken yobs, many of whom should never have been allowed to board in the first place.
Again, it's not considered important by airline management (I guess most drunks travel without doing more than pissing off their fellow pax, only a few end up getting hauled off in chains) so it's not worth the aggro for the crew or the ground staff, who know they won't get backed up by the airline should said drunken yob turn out to be a cabinet minister or reality TV star. The airline with the guests used to be particularly bad for checking in people who could barely stand; dunno if that's still the case. Of course there's no check in anymore so as long as you can hold it together for the five seconds it takes you to present your boarding pass, you're home and hosed.
