I think this is the most relevant link there.
35% of underaged teenagers who walk up to a movie theater and try to buy a ticket for a R-rated movie got one. 56% who tried to buy a PAL-rated CD got one. 47% who tried to buy an R-rated DVD got it. 50% who tried to buy an unrated DVD got it.
Only 20% who tried to buy an M-rated video game got one.
Anyone who thinks there's any sort of problem in the game retail industry is an idiot. The game industry is, by a vast majority, currently the most responsible entertainment industry when it comes to not selling products to children that have been marked as 'not for children'.
It is more than twice as easy for a 15 year old to buy Apocalypse Now than Fallout 3.
And note how fast the game industry has improved, and note the last poll was in 2008. It's probably even better now. Also note the more generic the retailer got, the more likely it was to fail the test...Game Stop was best at 6%, then Best Buy at 18%, and then other stores that aren't used to selling games near 30%. (Which the exception Circuit City, which was operated by morons, being higher, and Walmart, operated by prudes, being lower.)
I.e., the 'game industry' is fine, but electronic stores sometimes overlook checking, and giant chain stores that sell everything overlook even more. But even they overlook it a hell of a lot less than movie theaters do restricting movies! (And movie theater clerks, obviously, should actually know the rating of the ten movies they're currently selling, whereas some clerk in a Target can be forgiven for missing an M-rated video game they've never heard of in a store with a bajillion items in it.)