I was more than a bit surprised when I actually got some results.
It seems that high brightness LEDs are being strobed to disorientate suspects. The pulsing pattern and varying colours of the device temporarily blinds and nauseates the victim. This type of non-lethal is proving more effective than other forms of non-lethal incapacitor to neutralise suspects without any long-term effects.
A company called Intelligent Optical Systems based in Torrance, California have been awarded a $1m grant from the U.S. Department of Homeland Security to develop the concept further.
I think this is something that anyone designing LED systems should take a good look at - if you'd pardon the pun - as the last thing you'd want is to inadvertently release a puke-ray device onto the general market.
More info here http://science.howstuffworks.com/led-incapacitator.htm