I live in WI in a CWD zone. I am on the northern side of the CDW zone. We have had earn a buck in force in this GMU for about 5 years now, maybe more. (Don't want to take the time to look it up, but it's probably more than 5.) It has definitely decreased the deer herd in my area. There are less does, and less deer in general, but the buck ratio has gone up. The problem is that the overall deer numbers are getting progressively worse (substantially lower, buck or doe.) But I guess that is the intent of deer management in a CWD unit. If you are after a big buck, the good buck ratio doesn't do you any good, if you can't shoot a doe first because of low numbers. This is what leads to the cheaters, with double registrations, etc. In the past, I have gone without shooting a buck, as I have had difficulty in shooting a doe, any doe. Or, I have shot a doe, but then did not run into many bucks due to low population. I pass on the nubbin bucks to fulfill the EAB requirement. A gun hunter will not do that, on average. So if the intent of Earn a Buck is to battle CWD, it is probably the only tool that will work. I understand why they use it. If it is for other reasons, they should consider using it sparingly or not at all, as it will greatly reduce the herd within a relatively short period of time.
I really am disgusted in this whole CWD thing, as are most hunters around me. I have my theory on why and how CWD started in WI, but that would hijack the thread and probably start a brawl. If someone is interested in that, they can PM me. But watch out for that disease, it can really screw up your hunting.