Earlier this week, Steam introduced a change to its game-trading policy that forbids users from immediately trading video games that had been purchased as gifts.
Going forward: "All new games purchased as a gift and placed in the purchaser's inventory will be untradable for 30 day," Steam wrote on its official forums. "The gift may still be gifted at any time. The only change is to trading."
Under the previous setup, a game could be purchased and immediately traded to another user, who could then find their access denied if payment from the original buyer was refused. "We're hoping this lowers the number of people who trade for a game only to have the game revoked later due to issues with the purchaser's payment method," Valve wrote.
In some cases, resellers have bought up Steam keys to games with bogus payment methods, then quickly resold them to others. The end consumer then finds their access to the game revoked when Valve cannot process the original payment.