Remember, the key safety item with the strap is the ratchet is just there to hold it in place -- you want to wrap the strap itself around the trunk several times so if the tree tries to barber chair, the strap is tightening against itself and not relying on the ratchet to hold it together. And we're talking straps you'd use to secure loads to tractor trailers, not kayaks to your car roof. I know *how* to do it, but darn tough to describe in words.
Guess I look at the one and I'm concerned but not worried -- clear good escape paths on the up hill side so you can step back if you see it start to act hinky. Even if the tree barber chairs it's not going to do a back flip, it's going to fall on the trail side. It's not like a moderate leaner that could rotate around and land anywhere around the base when and if it fell, or catch you as it swings up.