Players should note, bringing Mornington Crescent into bounds during an out-of-bounds game is strictly against the rules, and so is winning. Therefore, one must employ a level of mastery of the rules far beyond that required of many other variants, or simply tire one's opponent into conceding.
[Darren]
It is worth noting that Mornington Crescent is always considered out of bounds, as winning moves can only be played when proper conditions have been met. Formalizing the 'out-of-bounds' convention may be handy in prolonging games, but this rule-set is essentially indistinguishable from so many others.
[Dr. Lock]
I believe the distinction is that in a game of Mornington Crescent Out-of-Bounds, one must first explicitly play a move that brings it into bounds – and anounce the fact – before later playing a winning move. In most other variants, bringing Mornington Crescent in bounds may be done implicitly, thus allowing for the possibility of 'surprise' victories.
[SM]