I don't know all that much about climbing... But what about the Bk2 do you think would fail this test? You think it's not strong enough to support 200+ lbs? I don't think that would even phase it.
I'm just curious to know what you think will fail. Knife comes out of the tree? Knife snaps? Something else?
Climbing gear has to support not merely static weight, but DYNAMIC force. It's about kinetic energy, not just holding something up.
It's one thing to hold a bowling ball. It's quite another to catch one.
There are a number of other not-greats in there. Generally you want your 'pro'(tection) looped around the widest point of the support with the least amount of leverage against it. If you ran the ROPE through the tang, the sharpish contours of the knife will wreak havok on that climbing line , making it weaker in unexpected places the next time, assuming it survives this climb.
Perhaps the choice of the 'biner is a 'good' one here?
The knife could flex the tree open while flexing itself, resulting in slippage. Nobody likes slippage.
Also, knives are relatively brittle tools, by design. The cross-sectional area of the blade where it meets the tree trunk is like .375sq" if you're lucky, but it's not round! Weird cross-sectional stresses on a hardened tool, where as climbing gear is designed for toughness.
And how do you get it out? If you can get it out, it wasn't safe to climb on in the first place.
Now if this clever joker had run the rope around the backside of the tree and down things would be better. Better yet, two opposing knives, canted slightly towards the edge of the cliff with two 'biners and runners going around the back side of the tree in opposite directions, allowing a balancing of forces on the downhill side while pulling the knives deeper into the trunk... but then why not just sling the tree?