Okay, just to keep everyone clear, leaving your basket of groceries on the floor in the checkout line while you go finish shopping does not reserve your place in line. Those are just abandoned groceries.
If you think I'm going to stand behind your stuff with my heavy basket while you wander the aisles for last-minute impulse buys, forget it. In fact, since I'm pretty sure salvage laws apply in this case, I'm much more likely to scan through your basket to see if there's anything in there I might like.
So, here's how it works.
1. Walk through the store and put the stuff you want in the basket.
2. Go get in line with your stuff, wait with your stuff, and pay for your stuff like everybody else.
3. Go home.
Oh, and when you DO finally return to your basket with your armload of bread, soup mix, bulk nuts and magazines, all your indignant passive-aggressive sighing and nose-breathing just supports my decision to take your box of Carr's water crackers. I'm having some now, and they are delicious.