If you plan the hunt for a dangerous animal, planning to use a bow/blowgun/throwing star/fists, *in a place and under such conditions where use of a gun in the hunt is illegal under the rules*, solely with the idea that you'll cause a charge, and have justification legally to shoot with a gun - in essense, just a subterfuge to hunt with a gun - then that's wrong and unethical and stupid. But otherwise, I have no problem whatsoever with people using whatever minimalist weapon they choose to, and have a backup/guide with a lead-spitting hammer of thor, in the event that it goes bad. If you're successful, then you took that griz with a bow. If you're not, then you didn't.
Having said that, I'm for truth in advertising. If you get the animal with a bow, then you should make the disclosure when telling the story that "and by the way, my guide was there with .500 eargasplitten loudenboomer". You will get respect, but deservedly, you won't get *as much* respect as the guy who actually shoots the griz all by his lonesome, armed with bow only (in which case you're fair to partly insane unless you're up in a tree stand, and even then...).
Sidebar: Get this - quite a coincidental story, considering this thread.... Went to lunch with a friend last Thursday. Couple of his buddies from his motorcycle "gang" (that's what they call it) show up to eat with us. One of these guys tells a story related to him by his brother in law (which he apparently accepts because he repeated it as gospel truth with an "aren't you impressed?" tone to the story). Seems that his BIL was hunting for "bear" with a bow in Canada (somewhere - he didn't know where - I asked). Evidently the hunt was for either/or black or brown bear (possible?), because the BIL got a 600-something lb black bear one day, then on the next day, he and the guide run across a brown bear at 15 yards. The guide proceeds to start yelling "shoot it now!" and so the BIL obeys and manages to get off either 5 or 6 arrows, from a compound bow mind you, into the griz before it drops 5 yards from them. And get this, all 6 (I think it was - but maybe 5) arrows hit the griz's vital zone. I believe the griz went over 850 lbs. Whew boy; I had to roll up my pants legs!