A friend runs a charity (no names - no pack-drill) which has a number of sites around the countryside which are open 24/7 for visitors. The sites have all got a traffic monitoring system that clicks over every time a car comes in through the entrance, and I have just helped him download this data from a reader onto his PC so that it can be used to measure visitor levels. The data is just the time and date of the arrival of the visiting car. No big deal here until we start looking at the data: this shows a fairly steady string of visitors, with seasonal and weather variations, during daylight hours which is what you might expect. What we did not expect was the high peak of visitors between 0030hrs and 0300 hrs. Given this is a countryside place with almost all the benefits being visible during daylight, what do you suppose is going on? Answers on a postcard please!