In shops I frequent, there is usually a single line for all 3-8 self-checkout machines, but separate lines for each individual cashier. I've noticed that the l

In shops I frequent, there is usually a single line for all 3-8 self-checkout machines, but separate lines for each individual cashier. I've noticed that the line for self-checkout is usually roughly the same length as the lines for individual cash registers, regardless of how many machines there are. I'm not sure if people just don't like self-checkout or if they have failed to notice that the "go to the shortest line" heuristic doesn't work anymore when one of the lines moves much faster than the others.