Yes, Alexei did raise that concern, since he's essentially an affective altruist that donates to MIRI anyway, and his donation to MIRI doesn't change anything. It's not like I can propose a donation to an alternative charity either, since asking someone to donate to the Methuselah foundation, for instance, would take that money away from MIRI. I'm hoping that anyone playing me and choosing the option of donating would have the goodwill to sacrifice money they wouldn't otherwise have donated, rather than leaving the counter-factual as inconsequential.