GameStop's practice of gutting new games and placing empty cases on the shelf has two side effects beyond prevention of theft: first, that a lot of customers are outraged when they receive an open box, and second, it allows employees to try out games without having to open a new copy expressly for that purpose, a practice that the company has allowed since before the store was called GameStop. We can personally attest to the policy being in place at Software Etc. stores in late 1998.
Kotaku contacted the Federal Trade Commission to determine if the policy of selling things as new that, in the strictest sense, were used, was unlawfully deceptive marketing. The FTC declined to comment about the practice or even if it is conducting an investigation.