I once had a passenger out of home base who was so obese he could not be loaded via the normal route. With 3 wheelchair attendants they could not control his chair on the gentle downslope of the airbridge so he descended to apron level in the passenger lift and was loaded into the aircraft via an ambilift vehicle at 1R. On entering the aircraft a couple more problems came to light. Although he had an economy ticket his size prohibited him from moving any further aft than row 1 on this A320 so he got an upgrade and was left in row 1. I did have some concerns that his weight was in excess of the seat load certification but I was assured by engineering that all was well. Once he was loaded door 1R was closed and boarding continued via 1L. When 1R was closed the previously refreshing draught from outside ceased. It was then the No.1 girl realised how much of an odour this poor fellow was giving off. The smell was indescribable. There were clearly areas of his body that had not seen the light of day for some considerable time, let alone any soap or water. In fact, he smelt like rotting flesh.
With boarding nearly complete the other 3 passengers in business class voluntarily downgraded themselves to economy to get away from the smell. At this stage I would have dearly liked to offload him as 'predjucing the well-being of other passengers' but I was assured that all company procedures had been followed and he was fit to travel...... Which means 'we don't want any bad publicity from offloading a wheelchair passenger'. As the flight-time was only 45 minutes we closed up and departed.
This was a pretty typical example of nobody on the ground wishing to make a call that was blindingly obvious..... Just like the passenger who has been drunk in the terminal for the last 2 hours...... but he is now OK to fly!