Imprint credit card from a delivery?

I thought we did away with imprints? I just ordered chinese food and I gave them all my info over the phone, then they wanted an imprint of my credit card when they delivered the food. I told them i would not give them an imprint because who knows what they do with those receipts. Or what if he drops it on his way back to the car??? Its not like they don't have your address if there is a problem with the credit card company. I don't see how this is legal, does anyone have any info covering this??