Charity Bikes

It seems like most of the bike builds on these shows are for charity, in some form or other. Either raffling off a bike to a wounded soldier, or auctioning off a bike for charity, or whatever.

This kind of suggests to me that OCC (or JPD) doesn't get enough business, so the producers have to bring in these charity builds.

This makes me wonder how these charity bikes work, financially. Does OCC get paid for them, or are they just donating? Does the foundation pay OCC? Or do the producers pay for the charity bikes just so they have a show?