That sounds like a solution looking for a problem. Anybody who was sprayed, even after they washed the orange crap off their face, is given away by the bloodshot eyes/red face/running nose and pungent smell. Also, I wonder how effective that would be if they put on sunblock[0] before the blacklight test.

[0] http://samanthagouldson.com/wp-content/uploads/2015/05/uv_an...