This is one I find really puzzling. I guess it potentially made some kind of sense in the days of the referral thing, where in the 1/1,000,000 chance they so loved your piece they just happened to find on Google and signed up for a membership you got a share forever/until they got bored and cancelled/their credit card expired. But now? I don't want non-members to even have their filthy cheapskate eyeballs even brush my works of art!