A trip to my local grocery store is an almost-daily ritual, as I hate to plan dinner ahead of time. The store is also a lovely 15-minute walk from my La Jolla home, making last minute dinner decisions doable without driving. The checkout staff contains familiar faces. When I recently forgot to bring my wallet to the store, I asked Bob if he would let me sign an IOU. He’s the round-faced 35-ish-year-old clerk who always looks like he is thinking of songs rather than codes as he rings up my produce prices. “After all, I’ll be here tomorrow … just like I was here yesterday.” “No way! It’s not our policy,” Bob replied, with a tone implying I was trying to pull a fast one over him. Did his response make sense in an era when Amazon acquired Whole Foods, and two-hour…