I've come to realize that when they come in and don't buy anything, take waaaay too long, or buy small things, they are shoplifting. Especially if you've never seen them before. Happened to me last week. Guy comes in, I was a little busy. He finally brought a 20oz soda and some Little Debbie cakes to the register. I rang up and bagged. He was the last one in the store. I decided to go have a smoke and walked out pretty close behind him. He was in front of the store, fiddling with the bag. He got on his bicycle and started to ride away. I saw a 1 liter Sprite in the bag. He didn't have it when he came in. I went back in and sure enough there was a Sprite missing. Hardly ever sell them. I had filled the Coke cooler not too long before, so I know what was there and what I sold(small store). Just keep your eyes peeled.