I am waiting to see if I got caught by a trap the other day. I drove to the local supermarket with my eldest son (14) and started shopping. After 10 minutes, I realised that I'd lost track of the time and that I should have been elsewhere to pick up my youngest son (9) from the school disco. I just had time and raced off, leaving my eldest to continue the shopping. Now obviously, he had no way of paying and couldn't transport bags of shopping for a family of five, even if he had, so I had to go back for him. I now have to wait to see if they try to charge me for breaking the "no return within one hour" rule, despite me only being there for a total of 25 minutes, with a 15 minute gap in the middle (3 hours allowed free).
Separate to this, one thing that has crossed my mind in the past is that I don't know whether the ANPR camera can give a good picture of who is driving. It is not beyond probability that my wife returns from shopping, realises that she has forgotten something and that I go back for it. If the car returns within the hour, but the driver doesn't, that cannot break the one hour rule, as the "contract" is supposed to be with the driver, but the ANPR system works on the car.
SteveW