See, that doesn't make sense to me. A private golf course (in the business of selling rounds of golf) donates a round of golf to a charity. The money that gets donated comes from a customer who is buying a round of golf. He or she pays for, and receives, a service. The golf course receives no money for the service they provide (which includes personnel, maintenance, insurance, property taxes, etc.), so why don't they get the tax deduction? Theirs was the actual donation, not the golfer's.
In the case of a private sailboat owner giving a ride to a charitable donor, I can see it as the opposite. The sailboat owner doesn't normally accept money for giving rides to friends and family, so the donor can be perceived as merely a friend who has made a charitable donation.
I know it's silly to split hairs like this, it's just where my mind goes sometimes!