>It's also much easier for anyone to shop at Costco with a spouse's/friend's membership card now that they have self-checkout. You used to have to worry about the cashier flagging you if the cardholder wasn't there, but now there's no one who even looks at your card.

Or how about don't be a liar/cheater and buy your own membership. It's not expensive and it pays for itself fast. Shame on whoever does this.