The reason they ask you to donate is to gather pricing data: If you're willing to donate, it means they can raise the price of the goods without hurting the dem

The reason they ask you to donate is to gather pricing data: If you're willing to donate, it means they can raise the price of the goods without hurting the demand curve. They actually do donate the money; they're not trying to keep your dollar. It's difficult to acquire this data via other means, so they don't mind paying it out properly.