I sense sarcasm in your post, but yes, it is possible albeit in limited circumstances. There have been cases where the defence has successfully argued that the GPS (which has accuracy limitations) and a counting of the makings on the road over a specified time period has introduced enough doubt that the defendant was judged not-guilty. It tends to be ones that are very close to the limit though, not all forces abide by the 10%+2 guideline and where you're arguing over only a few MPH, dashcam footage can make the difference.