I'd always thought that if you filed a flight plan (even VFR) you were supposed to stick to the route you had filed. However on a recent return flight from Dieppe we wanted to fly a different route than the one filed before leaving the UK. Dieppe was closed anyway so we took off and spoke to Paris Info to open the plan. We then asked if we could change the route at that point only to be told that we were VFR so could go whichever way we wanted.
I was confused! We flew the amended route anyway at that point. I thought the idea of a FP was so people know where you are likely to be if you don't turn up! Seems a but pointless if you can change the route without telling anybody! Nobody we spoke to en route seemed remotely surprised to find us on the route we were on!