Last year, the Federal Trade Commission ran a nationwide undercover shopping sting, aimed at testing various retailers' compliance with age ratings for media products.
Kids aged 13-16, without the supervision of an adult, were asked to try and buy things like unrated DVDs, explicit albums and M-rated video games.
For all the crap that game retailers often get in this regard - and I know as a former EB Games employee I saw my fill of parents buying young kids inappropriate games - it turns out game store (and retailers) were among the best in the US at enforcing the ESRB's self-regulated ratings guidelines.
While 30% of kids were able to buy adult DVDs and movie tickets, and 47% could buy explicit CDs, only 13% of secret shoppers could buy M-rated video games, which the FTC says gives video game retail "the highest level of compliance among the industries."