> What happened was the malicious failure of inadequate pressure vessels. Technically correct, but this quite accurately describes every bomb that isn't just naked plastic explosive / C4.

I do agree it's unfortunate that these devices get called bombs, but only because that word has too strong connotations. It isn't wrong: A bottle filled with dry ice is an "explosive device". The fact that it does not rely on an exothermal chemical reaction is secondary (albeit not irrelevant!): Else what would you call atomic bombs?

Also, let's not forget that these things could have caused injuries. Nobody might have died, but I sure wouldn't want one of these going off in my stall. (Plastic shrapnel and ripped eardrums, anyone?)