So long as that line is tensioned properly that fellow should be able to cut up to the hinge. Then pull the saw out of the cut, step down the ladder, put the saw away, move the ladder to a safe area, and then signal to pull the stub.
Ha, I've done like that at least a few times.
But, if said line is not tensioned enough, or tensioned too much, or the fellow cuts through the hinge there could be problems either way.
Even if done according to proper procedure there's a number other things that could possibly go wrong: the line or the knot could fail, if not set right, or there could be a nitwit on the other end pulling the tree. And that could open another can of worms altogether.
There must be a hundred different videos of the same scenario at youtube, and most of them end in some kind of screw up.
and sometimes people get hurt, bad.