I have a confession to make. I gave the incorrect GPA on my resume, back when I included it at all. (Getting numbers wrong is an occupational hazard of being part math major.)
Here's what happened: For my first summer internship, I listed the most current GPA that I had at the time. For subsequent positions when I updated my resume, I never got around to updating my GPA. My actual GPA was about three tenths of a point lower than what I reported. This wasn't out of any malicious intent to deceive, it's just one of those things that fell through the cracks. I didn't even notice that I did this until just today when (for the first time ever) I managed to get my hands on my own unofficial transcript.
Now, here's the funny thing. In all the time I've been working, no one ever called me on this, which probably means that no one ever checked. It's possible that no one ever could check, that GPA is confidential and the most a university can do is to verify that so-and-so attended in such-and-such a year. When you apply for a university position, at least, some of them require you to send an unofficial transcript as part of the application package -- which is how I came to notice my own transgression.
This would seem to imply that I managed to get by in the industry on the strength of my experience and my interview skills, and little details like grades didn't matter much. To which some students will say "Great! Then I can stop spending all of my time studying, and just play more Halo 3, since it doesn't matter anyway!" and other students will say "You mean I can just put that I got a 4.0 on my resume and they'll believe it?"
I would say no to both.
Why not to falsify your resume: even if the odds are low that it will be checked, if you apply to the one company that asks for a transcript, you're in trouble -- it's a small industry, and people will talk. I at least had plausible deniability; if you're a C student pretending to be on honor roll, it's hard for you to say it was an accidental typo.
Note to people in industry: check references of new junior hires! Seriously. Some people will lie. Even if they don't, when I offer to be a reference for one of my students, it means I want to be contacted so I can give the honest dirt (and, honestly, so that I can then contact that student and let them know that this company checks references, which is a good sign that they might make fewer bad hires than average). You may not be able to verify their GPA, but at least verify what you can.
Why not to slack off and stop caring: because your education might not end when you get your Bachelor's degree. Maybe you'll want to head directly to graduate school, where your GPA is most certainly a factor in which places you can get into. Maybe you'll delay awhile and decide to go back to school later; even if you're burned out on school now and don't think you'd ever want to do that to yourself, time might change your mind. Maybe after your requisite 5.5 years in the industry you'll decide to go into teaching (like I did), where your previous degree(s) and your GPA are a factor. And yes, being able to put a big number on your resume might be the one last excuse a game company needs to hire you.
Oh, and I should add that the stuff you're learning in college is actually useful (even if you can't see why right now, since most teachers suck at showing the context of their subjects) and the same actions that get you an A are those actions that actually help you learn. Most of the time.