Once, when I visited a fair with my cousin sister. We went to a swing and were disappointed to see that the controller or the operator had gone out some where. I took my seat in advance and my sister went to the control room. She clicked on one of the switches and the swing started. I started shouting. Hearing the voices, the controller/operator came and asked my sister why she had started the swing. My sister cleverly replied, “I thought there was self-service on these swings!” The controller had nothing to say. We had a good laugh after that.