Well, given this:
I just feel very strongly that we as responsible parents need to protect our children from garbage like this!
...it seems the OP is concerned about "children" in general. Of which 17-year-olds specifically (the only
minors who should be playing this game) are only a tiny subset. Also, assuming the cousin in question is a minor odds are he also isn't 17 specifically.
Of course, here is where on a more gaming-oriented forum we could have a lively discussion on just how absurd the age cutoff of 17 is for M-rating, given that AO (the "adults only" rating, generally reserved for quasi-pornographic or just plain pornographic games) has a cutoff of 18. Because of course that year is just
critical, right?
But yeah, the key to "protecting our children" from videogames is recognizing that the "M" on the front doesn't stand for "monkeys." It's the equivalent of an R rating from the MPAA, and signifies that more than likely if your worried about "protecting your children" then this game isn't appropriate for them. And the reason that I don't think legislation is necessary (like the proposed mandatory ID checks) is that a
vast majority of the time, based on my experience handing out games at both retail and rental, the parent
is present when the kids get these games. And I'd wager a majority of the rest, the parent knows the kid has the game.
It's not like the average kid is hiding the copy of GTA 4 (or 3, or Vice City, or San Andreas) in a secret compartment in their closet, and only playing it while the parents are gone. More often than not the case is sitting on the kid's shelf, the disc is in the console, and they're playing it while the parents are in the next room (or across the house). The game is clearly labeled as to the content, and six seconds spent browsing the back of the box should be more than enough to convince any concerned parent as to the appropriateness (or rather, lack thereof) for their child. Failing that, four seconds spent on google should erase any doubts.
So yes, by all means do
not let your kid buy/play this game.
It's not meant for them, and is clearly labeled as such. And I wholeheartedly support your boycott of the game...though again, I find the idea that it's the "omg makin' fun of 'publicans" part that really put you over the top pretty absurd.
Disclaimer: I actually don't particularly dig the GTA series anyway. I think the gameplay is largely crap, and that the series thrives on shock value more than anything. But I haven't played 4 (or much of VC or SA), so maybe that's changed.
Also, it should be noted that Capcom is just the publisher, and that Rockstar is the developer. While it's fair to hold Capcom partially responsible, at that point you should
also start looking into what the subsidiaries of some other companies are involved with. An easy example is Disney, and some of the things that get published under studios/labels they own. The only difference is that Capcom doesn't try to hide it.