If I had my way if you are intoxicated in any way you should be denied boarding
They are, or at least should be. Anybody turning up intoxicated should be refused carriage. I know that happens regularly (more regularly than people would think). It is illegal to be drunk on board an aircraft, so the gate rep would not be doing their job correctly if they allowed them to get onboard (I know it happens, but it shouldn't and it is reducing).
On a final note, quite often people will arrive at the gate and will be quite ok, but we all know it takes a while for the affects of alcohol to take effect, so if someone had just downed a few shots prior to walking to the gate they would show no ill effects, half an hour later, passing 20'000 feet in the climb and all hell breaks loose. People think then that this person must have been allowed to board whilst intoxicated, but he/she wasn't at that time.
Jet2 might well be in the news regarding this issue, it does NOT mean that Jet2 attract these types, it merely shows that we are being positive in trying to stamp it out, and perhaps those undesirables who read the trash tabloids where these stories are iften covered might just get the message that behaviour of this type will not be tolerated.