My parents never bought games for me (except Neverwinter Nights), and I've always been so much of a wuss that most rated M games didn't attract me either. Recently when I bought BioShock though my mom had driven me to the local EB Games and I ran into a slight problem, seeing as how she had ownership of my money at the time. (Why? it's a long story involving IOUs and un-cashed checks.) Basically the event went like this:
"Mom: Did you find any games you wanted to buy?
Me: Yes...
Mom: What is it?
Me: Uhm... BioShock. *hands over box carefully* It's apparently a really good game and very atmospheric and stuff.
Mom: Rated M for violence and blood? ...I dunno, couldn't you pick up an adventure game or something instead."
Lucky for me I can put up with adventure game bullshit to such an extent that I enjoy adventure games, so I added two games to the pile. Then the following happened:
"Mom: ...these look sorta weird. What are they about?
Me: Well... this one, Outcry, is about pseudo-science and trying to find your brother. This other one, Darkness Within, involves you following a killer and is very Lovecraftian.
Mom: Oh... okay, so why don't you just buy these two?
Me: Well, sure, but I could buy all three. But in terms of content, Darkness Within is probably as scary as BioShock. And the violence in BioShock isn't any worse than in any other similar game I played except that it's with newer graphics so the "realism" factor is up a bit more, but it actually will end up falling more into the uncanny valley because such realism makes you use your imagination less so things are simply their face value.
Mom: Yeah okay, that makes sense. Sure."
That was the only time I've encountered restrictions as to what games I could buy. And I talked my way out. Then again, my mom never actually sees me play most games... Good thing too because everything I said about BioShock not being scary or violent was bullshit. >_>
As for my dad? Well he walked by me as I was fighting a headless in Dungeon Lords and was just like "Huh. Cool."