I just want to second this. What I've seen for the last few months that I've been on here is that for most, this is their first serious UAV. The P3 is phenomenally easy to fly in full P-GPS, so most newbies get a little spoiled and fly in this mode pretty exclusively. Putting together that point and the point that most have never flown anything else other than maybe a toy UAV makes for a lot of crashes when the P3 flips out of P-GPS when experiencing an error in the automated flight mode.
Also seems like the first thing many do is to press RTH when this happens, which is the worst thing you can do when the UAV is confused. Even though I have owned and flown many other UAV's, I make a conscious effort to fly in ATTI mode for at least a few minutes each day I fly. I am confident that if I ever experience the errors that some have had and the P-GPS mode is unavailable, I can bring it in if necessary. I would advise all those new to UAV's to do the same.