...on the 50 move draw rule in chess.

Source:
http://en.wikipedia.org/wiki/Fifty-move_rule

"The fifty-move rule in chess states that a player can claim a draw if no capture has been made and no pawn has been moved in the last fifty consecutive moves (fifty moves by each side). The intended reason for the rule is so that a player with no chance to win cannot be obstinate and play on indefinitely (Hooper & Whyld 1992), or seek a win purely due to an opponent's fatigue. All of the basic checkmates can be accomplished in well under fifty moves.
In the 20th century it was discovered that some positions of certain endgames can only be won in more than fifty moves (without a capture or a pawn move). The rule was changed to include certain exceptions in which one hundred moves were allowed with particular material combinations. However, more and more exceptions were discovered and in 1992 FIDE abolished all such exceptions and reinstated the strict fifty-move rule."

I hope it's not a problem that I copied the text and pasted it here.
The point is that though it was found that a game could be won beyond the 50 moves, the 50 move rule was eventually reinstated. Again, this rule ensures that a game must progress or a player will have the right to call a draw. I assert that such reasoning applies or should apply to Espionage as well.