My wife doesn't do that, but she does the next most scary thing- she continually offers to buy me any Transformer I want and she asks which is the most valuable and hardest to obtain.
I'm not about to take her up on her offer because I believe these are my Transformers and I want to be buying them myself. So I told her that she shouldn't buy me any Transformers just in case she mistakenly buys me one that I already have and that would be a waste of money, heh.