Heard a great story the other day.
My friend went into his local pub and ordered a pint of Brains Reverend James. Knowing that the beer is usually an brown, amber colour, he was curious when the beer poured a light golden.
The barmaid was non-plussed and could not help but the manager was more forthcoming. The beer was in fact Brains SA Gold but they had been unable to find the correct pumpclip that morning so decided to use the Reverend James one as it was the same brewery and near enough.
The correct clip had been found and replaced by the time my pal left the pub.