When I was trying to get my Brooks to work on my road bike, I asked Wallingford if they'd accept it for return if it was cut, and they said they would. However, they do sell returned saddles on ebay to cut their losses, and a cut-up one probably wouldn't sell, so they'd be taking a hit on it.

His response guilt-tripped me enough to hold on to it & use it on my commuter, which is much more upright than my road bike, so I don't need the cutout.