I posted a message on the Gammon Discussion Board, asking for doubling to hasten resignations!!

It occurs to me that a double feature could work for any number of games, where guys in totally lost positions just go on and on. Halma and Reversi are good examples.

by all means let them play on - but the possibility that they could lose 'two' games (with the consequent effect on their ratings) could make a resignation decision very easy!