Extreme - Explosives are used to remove material from stone fissures.
Please add -- and not just because of the quoted line -- a category for the environmental damage you might leave behind.
I have seen
landscapes -- especially out west, but including one at a mountain park
in the southeast -- pocked with holes and broken rock shards from collectors who had more interest in their booty than in the mess they left behind for others to find and see. This can be caused just as much by picks and prybars as by a stick of dynamite.
Frankly, I can't imagine a bonsaiest being so greedy that he (I doubt it would be a she) would stoop to using explosives to get a TREE for his collection, and if I could imagine it, I'm quite certain I would have no interest in knowing or associating with that person. And if they were used for commercial collecting . . .
Sorry, but this is one of my important triggers.
I call to your attention my "The Ethics of Collecting" in the Winter 2000 (vol. 34 #4) issue of the Bonsai Journal.