If I go home and write in my diary that today hekfu bought lots of broccoli, you don't have the right to come to me in five years and demand that I remove all mention of you from my diary at my own cost.I asked this question in a comment [1] here on HN a few weeks ago. There were affirmative responses that yes, the shopkeeper should in fact be held to account for keeping notes on who came into his store.
[1] https://news.ycombinator.com/item?id=16509598