On Friday, June 10, 2016 at 10:01:15 AM UTC-7, Jonathan St. Cloud wrote:
Wild hypothetical, what if GPS gaming is going on durning a contest and some or all contestants lose part of the logging of points on course? Years ago I was denied a Diamond distance/goal because of about four minutes where the Cambridge logger didn't log. I returned and flew that segment of the flight but was still denied. It was obvious that I could not have landed and taken off again.

Also, does the GPS jamming affect 406 ELT's? What about planes on IFR plans solely using GPS for navigation?

406MHz ELTs with GPS... sure possibly. But all 406MHz ELTs are also capable of SARSAT/COSPAS doppler location and have 121.5 MHz homing beacon. Practical impacts on air navigation are a much higher level concern.