People definitely gets these calls to see if they want someones cancellation, it's clearly not done in the order that your order is placed either. From what my lease companies contact said in an email, it's usually done on order date but based on the cars collection location, especially at the very end of a quarter.
For example, if someone that's had a car delivered to Manchester then cancels of doesn't collect, the next person in line to collect from that location gets a call. Maybe its possible to get real lucky at the SC but who knows, the explanation above could also be rubbish, it does make perfect sense though.