Getting said pilot off the plane on the day I think is only the start of the problem for those colleagues that would find themselves in this situation.
Be interesting to hear how people would handle this scenario themselves. Perhaps more so the guy that you're reasonably confident is a bit on the nose but is fairly normal otherwise.
Do you suggest that he stand himself down in the hope that it's a one off and risk the possibility that it's not?
Do you refer them to management and risk their imminent dismissal?
Do you call security and have them tested when you're not even sure they're over the limit? Perhaps there is a medical condition that they're predisposed to?
I think even in advanced countries like mine this is a real legal and ethical minefield?