I recently watched some older video of gran tours and major races and noticed that people bringing colored smoke canisters is not as new of an annoying phenomenon as I thought. I was bummed out at recent events, including world championship that " fans" bring smoke bombs and find amusement in making racers ride through it.. Don't know the solution..
Like I've mentioned previously:
If anyone is caught doing so, put them on a stationary bike, and make them go as hard as they can, while blowing smoke in their face.