Yeah, as an ex GS employee - GS does not have the profit margins on new games to do a sale like that on new games. Only used games get put on buy two get one sales, and those can be returned.
So this is definitely a /thathappened moment.
Also like... How old is this post? Even when I worked at GS years ago parents knew what CoD was. The first CoD came out in 2003 it is not the kind of obscure that parents would ask about.