Well I don't know about a 1300 beating a 2700 but in my case a 1750 player I have played some 1000 rated players who play so loose that the unexpected can happen (Akeetam for one). Lost to a 1300 player playing too safe recently and been so up in material in one game my position became swamped by my own material.
You talking about online ratings? Because I wouldn't expect to lose 1 game in a hundred (accurately) rated 1000 in online turn based on chess.com.
I'd be impressed to see a 1300 player beat one of the strong computer programs in my above diagram, and that's a bad blunder for a GM, which wasn't easy to capitalise on.
You have a point, I have not actually lost to a 1000 rated player, however I think the point I was trying to make was that, someone playing so illogically and haphazard it's possible to fall into accidental traps that the 1000 player had no idea they had created.
I was a 1600 rated player and still beats a 2000+ rated opponents.