Presumably the only reason someone wouldn't instantly set off a demo they have built on an HQ would be to wait for your blob to retreat so they can take some troops down too OR you kill the squad laying it just as they finish so the other player doesn't have time to trigger it?
Are there often cases where a demo is left undetonated on an HQ?
demo on schwer headquerter. why ? because if they blow the demo by mortar it's should have left only 5 hp
Mr.Smith also put one on my fuel cache lel it's like hand me a revolver to smoke myself