My wife and I have a ball doing this. The last time we were together and bought someone's meal, it was a young couple with a couple kiddo's. I walked over to the table and ask if I could see his check for a second and he looked at me puzzled and said sure. I took it and walked off, while the young lady ask who is that and what is he doing? As I walked past them leaving they sat their with silly looks on their faces. We try to do this at least once a week. There is no way to get more in your hand if you have it closed tightly on what you currently have.