I guess you change the odometer less than you use it, so it looks like you've only done 1,000km in the last year when actually you've done 10,000?
I wonder if the new speed cameras that record your number plate could be used to check for odo changes? Like if they know you drove through that 10km (or whatever) zone twice a day every day, they would (or at least could) know that you've driven 5,000km over the 250 working days so they could tag you for closer inspection or something?