I think it is obvious that deer can be killed in Carharts, I have done it myself. But there is no way to judge how many times you have been spotted (with or without camo) and never knew it. Another thing to take into account is comfort. I would rather be in Carharts and be able to stay in stand all day then to have some camo and freeze to death in an hour. If the warmth is the same I don't think anyone will say that camo is less effective then Carharts.