lemons

When a buyer cannot see quality before paying, sellers bring their worst, so the price falls, so the good sellers leave — until only the bad goods (the "lemons") remain.

Economists call this the market for lemons, after George Akerlof's 1970 paper on used cars; the cure is anything that lets quality be seen or promised — inspection, warranty, reputation. The castle's copy of the idea is sharper still: even inside one declared quality band, every rational seller delivers the worst the band accepts, so a bid on a band is really a bid on the band's floor. The defense is eyes at the door: verify on intake, because a card can lie about its condition and an NFT cannot.