I have tried to do this before. (Manually, but still.) It does not work. People genuinely want to buy you useless junk you don't actually want.
I've tried it too, although I've said to donate to a charity of their choice in my name. In retrospect, I wonder if making them choose made them more or less likely to give...
Honestly, if it was up to me (and I didn't have any kids) I would probably just skip Christmas entirely, save the part about eating a bunch of nice food. Spending a bunch of money on family that I only see at Christmas (purposely) and chopping down a perfectly good tree, dancing around it singing songs in honor of a nonexistent diety whose supports have murdered people I respect by burning them on the stake is just not my idea of a great time.