Over the weekend my wallet got wet and I had to empty it out to let everything dry. With the contents spread out on the table, I noticed that more than half of the items I was lugging around were cards for some kind of loyalty program: a few plastic store cards, countless (now soggy) paper punch cards and even two tiny ‘keychain’ size plastic tabs stuffed in a small pocket. A few of these are for places I shop at frequently – notably the grocery....