If they're serious they should dump the cash into a trust controlled by people outside BFL. Or they should make sure to give a few BIG chunks of that cash out immediately to worthwhile causes like zerocoin. Charity in my mind was like cancer treatment or hospitals or something...
+1 This.
They should use an escrow to prove they have 1000 BTC to donate and have that escrow donate it on behalf of them publicly so there is no funny business.
John could do it.
Likely BFL doesn't want to do this because it involves an honest 3rd party to keep things transparent.
I originally didn't have a problem with BFL creating an external charitable organization, but you're right - all celebrity charities are run by an external board. BFL too may need to set this up, otherwise it could be seen as a way of money laundering or tax evasion.
I, personally, like the idea of the 1000BTC donation going to an organization which then doles out smaller donations to the community. But that organization's choices should be independent of the group funding it, and maybe it will be.