All-D is the /optimal/ strategy for Memory-0 - but if your goal for Memory-0 interactions is merely to avoid getting the Sucker’s payoff, and /also/ to be able to deal with Memory-1 strategies, then defaulting to All-C versus All-C isn’t that bad a compromise.
All-D is the /optimal/ strategy for Memory-0 - but if your goal for Memory-0 interactions is merely to avoid getting the Sucker’s payoff, and /also/ to be able to deal with Memory-1 strategies, then defaulting to All-C versus All-C isn’t that bad a compromise.