It's an interesting moral issue as well.
I suggest you post recommendations on how to join the team anyway.
Then, we can sign agreements that we'd donate money to ExI.
Or we just work as a collaborating bunch of individualists, and the winner if any, does what s/he pleases (I think that would be the preferred option).
We could also agree on a partial donation to ExI, form two teams, form a team where everybody pledges what they want, etc.
I will definitely join on a no-strings-attached condition, and maybe on others as well.