If planning permission was conditional on the Travel Plan being approved - which one can only assume will change as different people attend the nursery over time - it would seem perfectly reasonable to have review points. If this is not the case, it would make the requirement for a travel plan a complete waste of time but might explain why monitoring customers travel to and from the nursery has been witnessed. It sounds like the council have encouraged this behaviour (so much disliked by customers) by making a this part of the planning approval criteria. It may of course be completely irrelevent now permission had been granted, but it is an example of how rediculous planning rules can be, if this is the case.