I used to be in a troop that had an explosives experimenter, though he didn't use gas cannisters.
Another anecdote warning:
I was never a Scout, but once spent a memorable night on an island run by sea scouts. It was the sensible, ex-RN person in charge who threw two gas canisters onto the fire at the end of the evening. He did get us kids to stand a safe distance away - though I'm not sure how safe, at least one of the cans landed in the trees behind us.
Come to think of it, I never found out why our group didn't go back there.
I gather the valved gas cans are much less interesting, since the valves are designed to vent excess pressure so they just release a jet of flame every few seconds until the gas runs out.
No, I haven't tried. Yet.
Everyone's ghast should get a good flabbering now and then.