I’m almost certain I’ve heard stories about soldiers eating or even burning c4^1 for shits and giggles. Not surprised they have to put a warning label on it, though I doubt it does any good.
^1 : iirc c4 by itself is very safe because it has to be exposed to a sudden increase in pressure and heat to detonate (e.g. a shock wave, or supposedly, stomping on it while it’s on fire). Just burning it or throwing it at a wall won’t make it explode.