@Hoss @Hyperhidrosis Nothing, if in the US. The basics is that in the US it's generally legal to use it unless people can be misled by it's use (so don't spray it on a van and then drive it around during an emergency situation). What would probably happen is that they would instead try to limit it's sale outside the US. It's easier to just change the color.

Outside the US the story might be different though.