The GPL does not forbid charging money for software; it only restricts additional charges made for access to the source code. So if I want to sell GPLed software for $20, a Federal Reserve Note bearing the visage of Andrew Jackson becomes a "certificate redeemable for GPLv3 software", and everyone who spends one is now bound by the GPL.
Another bad analogy -- money is not a "certificate redeemable for GPLv3
software" -- it is legal tender that can be used to purchase ANYTHING
-- are you saying that having money to purchase anything makes you as
closely-related to the "conveyance" of all purchased goods as MS is to the
redemption of Novell SLED coupons? Bit of a stretch, if you ask me.
This is why I went for the gift certificate analogy in the first place. A gift certificate is a promise made by its issuer to provide some goods and/or services to a third party, who could otherwise purchase same for cash. These vouchers, issued by Novell, grant permission to receive support services, including downloads of updates from Novell's servers, which would otherwise require payment to Novell. It is Novell that makes the promise, and Novell that makes it good. Microsoft does nothing to make itself liable for copyright infringement, either primarily or secondarily, by reselling these certificates, any more than I make myself liable for health code violations at a McDonald's by redistributing or reselling their gift certificates or $20 bills.