Set up a position on a scratch board, e.g. white: Ka2, Qa3, black Kb5 and try to play against an engine, e.g. Crafty. Eboard sends this position to Crafty with KQkq castling status (that is, castling is available on both sides), Crafty responds to any move with the message 'illegal move', ignores this position and continues to play as though we started from the standard initial position. If there was a way to edit the castling status in the scratch board, Crafty would not get confused.