What's the snallest possible program that accepts a chess board state and prints any legal move? True randomness may only have a couple hundred ELO, but then, that's pretty big for golf
I'd claim it would work on human opponents, but I think it would get banned from chess tournaments.
The problem isn't really well defined. Elo rating is assumed to be determinable independent of what opponents you face, so scoring 50% against opponents rated 1800 gives you the same information as scoring 26% against opponents rated 2000. In practice that's obviously not completely true, and for degenerate examples like the ones we are discussing it completely falls apart.