This may be a sensitive subject, but I have been seeking clarification from Lockheed Martin on the allowed uses of P3D. John Nicols publicly said:
http://www.prepar3d.com/forum-5/?mingleforumaction=viewtopic&t=682
Bottom line, don't use it as a replacement for a game, it needs to be used for non-entertainment purposes
http://www.prepar3d.com/forum-5/?mingleforumaction=viewtopic&t=682