It's certainly been speculated about since 2012, at the very least: https://www.reddit.com/r/tf2/comments/134u4d/1111_key_injection_and_economy_manipulation/c70

It's certainly been speculated about since 2012, at the very least: https://www.reddit.com/r/tf2/comments/134u4d/1111_key_injection_and_economy_manipulation/c70v4xc/ https://www.reddit.com/r/tf2/comments/134u4d/1111_key_inject... However it seems to have attracted almost no interest from journalists, for whatever reason. OTOH, since "worldwide fraud networks have recently shifted to using CS:GO keys to liquidate their gains" probably has at least some basis in reality, what's the story there? What other methods are criminals (presumably) shying away from now?