The trouble is these passengers are passed down the line like a game of 'pass the parcel'.
Check-in clerk - are you drunk? 'No, I'm fine'
so on to Dispatcher
'No, I'm fine'
Further enquiry, Dispatcher askes Cabin Crew 'what do you think?'
Time goes on, bags loaded.
Cabin crew may ask Flight Deck.
Has s/he got bags - 'Yes'
Captain, well if we have to unload him/her now we'll miss the slot.
Passenger boards.
On one flight a few years ago one such passenger was boarded at Luton. Full aircraft with 148 pax bound for England match in Amsterdam.
Said passenger became abusive and did not remain seated after cabin secure.
We decided to turn back after lining up when cabin crew told us passenger was in a fight with another pax.
Slot missed, match missed, one pax off-loaded (nutter - it took 4 policemen), 147 other angry to deal with now!
Where do you draw the line and hindsight is a great thing.
No one wants to take responsibility and 'deal' with the problem. The buzz word is 'ownership' of the problem.
Can't blame the staff/employees all the time - they are human. Maybe management should interface with passengers more often and see the 'tolerant' approach for themselves - take ownership.