RE: GIANT DEER!!!
Great deer!
I would say that legally buying antlers might provide an incentive to illegally harvest bucks. That doesn't mean that we shouldn't be allowed to legally buy antlers. Instead, it becomes a matter of enforcing the hunting laws already on the books related to taking deer.
Many sporting goods stores use replicas of antlers or accept antlers as donations, instead of purchasing them for that very reason.
I wouldn't personally buy any antlers that I didn't harvest, nor will I sell any of mine.