Airport

As I flew out for Thanksgiving, I stopped at a news stand to get some magazines. The sales clerk was very friendly to everyone in the store, so I thought nothing when he greeted and tried to help me.
As I checked out, he asked me to fill out a 'customer satisfaction survey,' which I was happy to do. He'd been friendly enough, I didn't mind giving him a good review. I filled it out, but left the optional parts asking for name and address blank. I handed the form to him and left.
Then I heard a shout from behind me. The clerk was calling me back in, saying I'd forgot to put something down. I walked back, annoyed, (I was trying to catch my flight, after all) and asked what I'd forgotten. He pointed...to the spot for my phone number. When I looked up at him, he smiled and winked.
What could I do? I told him no, angrily, and went to go through security.