How about #59: "Free advice is seldom cheap." Because you're basically saying that there's no such thing as free, and it's simply an 'unclarified financial contract to be consolidated at a later time.' Quark would approve! If I'm paying for a friend's lunch it's because I want to, not because I expect anything from him in the future. And beyond that, I do not consider downloading something somebody has released for free as establishing a relationship.
I prefer #68 here: “Compassion is no substitute for a profit.” The donation is compassionate; retaining it would be more profitable.