Would much rather have it made out of material that would explode in their face when they try to light it. There’s a great video (don’t know where it is now) of a guy trying to burn an American flag and HE gets caught on fire.
A flag that can defend itself would be a very American idea.
There are some good “flash burn” materials that would just poof and disappear when exposed to fire or flame. Blend them with something that makes nasty smelling persistent smoke when burned.