In downtown Calgary - as in Toronto, and no doubt other cities - they have replaced meters with machines that you pump money into to be given a chit to put on your dashboard. In Toronto, people would give chits with remaining time on them to others, or leave them in obvious spots - the evil geniuses of parking-machine manufactury have defeated such attempts at neighbourliness by creating machines that require you to input your license plate number, which is printed on the chit.

There is a mildly amusing variation of that in parts of the UK. Years ago that sort of system was introduced in some places, but in the interests of keeping the machines cheap they only had a numeric keypad, and you typed in the three digit numerical part of the licence number. So far, so bad: there was only about 1 chance in a thousand of your being able to give your ticket to someone else. Not very long after, the whole scheme for allocating licences changed to a two digit system, where the digits encode the year. This meant (providing your car is less than about eight yesr old) you are now nearly certain of being able to give your ticket to someone again.