If you handle enough queens you'll see on faint now and again. I've seen it a few times. Here's Jay Smith's theory:
http://www.bushfarms.com/beesqueenrearingsimplified.htm#fainting
"The Question of Cataleptic Queens.
"In handling queens, many beekeepers have observed that once in a great while a queen suddenly becomes unconscious and sometimes dies. The reason assigned is that she took a cramp or had a cataleptic fit.
"The author has observed this for the past twenty years. Some seasons it would occur but once; during others half a dozen times or more. In my mind there has always been some doubts whether or not the queen was cataleptic. One season, the loss was heavier than usual. One day two were lost. I say "lost" as the queens were always discarded after having a "fit," for previous experience had made me believe that they were permanently injured by having these "spells."
"The day the two queens were lost, I observed how very similar was the action of the injured queen to the one that had been stung by another queen. There was a sudden collapse, then a slight quivering of the legs. In one case this lasted for over half an hour, when the queen slowly revived. In the other case, the queen quivered four about the same length of time and then died. It seemed certain to me that in some mysterious manner these queens were getting poison from a sting. Could it be that the poison on my fingers from worker-stings was causing the mischief? Investigation failed to substantiate this. I noticed that in one case the queen had taken hold of the top of her abdomen with a front foot, which might indicate that she had received a slight prick in the foot from her own sting. I therefore watched carefully and soon this belief was confirmed. The queen in taking hold of the tip of her abdomen exposed the sting. Then, in trying to get hold with the rest of her feet, she would strike right at the point of the sting. In this manner she undoubtedly received some of the poison. Since that time we have taken great care that a queen is not allowed to take hold of the tip of her abdomen, consequently no more queens have been afflicted with fainting spells."--Jay Smith, Queen Rearing Simplified Chapter XXV