Unattended Bus

Arrived at the bus stop to catch the 11a. The bus was already at the stop but the doors were closed. I noticed a lady passenger sitting on the bus but no sign of the driver. The bus was sitting with it's engine running. I thought I'd imagined it so I went to the rear of the bus to check. How daft was that, it only takes a second for some little scumbag to push the red button, doors open and the bus is away (OAP and all). About four minutes later the driver arrived (Think he had been in the coffee shop near by).
I was going to report it but the driver turned out to be one of the pleasant ones. (Must have had a caffeine fix)