If someone (gamer) likes a developer/artist’s work so much, he/she should be able to send donations to that developer/artist.
As there is no company or organization (in US foundation) the donations cannot be send to a central place.
I’m fairly sure they aren’t allowed to do that for legal reasons, as well as ‘we don’t want your money’ unfortunately I can’t back this up due to the wipe, but that’s why there isn’t one if I remember correctly
They can not accept any money from the mod because in essence it would be like the sale of Valve’s Intellectual Property and that would be illegal.
We could always send them some cookies though! Or maybe a case of beer? 
No donations.