No matter what strange circumstances and situations we might dream up the simple fact is that a 1300 rated player has only a tiny chance of winning against someone rated 2700, and no chance whatsoever of outplaying them.
They could only win through exploiting a catastrophic blunder. But strong GMs tend only to make catastrophic blunders when they have been put under sustained pressure by another GM.
According to the Elo rating system a 400 rating point difference means the higher rated player will score 100% or very close agaisnt the lower rated one. To have a realistic, if tiny chance, of beating a 2700 hundred player you need to be a genuine 2300+. Has anyone ever seen a rating jump from 1300 to 2300+ in one go, or know of a child prodigy with a 1300 rating that is playing at 2300+ level. I doubt it. But if one existed, and was playing a Super GM, I think the super GM might just know something about the true strength of his opponent.
Short version:
1. Players new to over the board, but not new to chess and
2. Sandbaggers
The sandbaggers are to weak. There are some class B players, sandbagging to win in class C and collect prizemoney, but class A does not sandbag that deep.