For the last 15 years or so, probably 95% of my calling has been with a scope equipped with parallax adjustment (AO). I've only very, very rarely had occasion to use the AO on a scope while coyote hunting. And it's always been when taking a very long range, very deliberate, very calculated shot. But, by the same token, I've never, ever, not once had the parallax adjustment hurt my chances of killing a coyote. Even if it were accidentally set for infinity, and a coyote popped up at 20 feet, it wouldn't make any difference - you'd still be able to obtain a useable sight picture and get the job done. The more common, more likely scenario of having parallax (AO) set for 400 - 500 yards, and a coyote that needs killing inside 50 yards, it just doesn't matter. It's happened to me a handful of times. Sure, the sight picture is a bit fuzzy, but not to where it has ever saved a coyotes life in my experience.
Anyway, I agree that AO isn't a feature you really need in a scope for coyote hunting. But it hasn't ever hurt me either - I sure wouldn't "disqualify" a scope just for having it. In fact, higher quality scopes in the magnification range I prefer pretty much all have parallax adjustment. To avoid it, in my case at least, would be to remove some darn good scopes from consideration.
Leaving the magnification cranked too high has in fact cost me one or two coyotes over the years. Or at least cost me the chance for a decent shot opportunity.
- DAA