Hilton, Marriott, Holiday Inn Express, Cobblestone were all represented. Piled amid the discarded receipts for stamps, groceries, and nights on the town, plus loose change and an assortment of pens whose ink had long ago run dry, was the pile of hotel key cards. Someone had told me never to leave them behind, so I had packed them up and brought them home. On Friday, it was time to purge them,…