Good idea in theory. In practice, it really doesn't happen this way. I see it all the time at my college (which is a lot like the SAs academically - very selective, rigorous, smaller number of majors and programs). Freshmen all take a math placement exam. They can opt to take the course below the one into which we place them. In fall 2014, 121 of 762 incoming freshmen did exactly that. Of those 121, 52 earned a C or below. Now, these are not slackers or students who need developmental math - they're choosing algebra instead of pre-calc or pre-calc instead of calc I. No, what's happening is simple human behavioral economics. "Whew, I'm in an easy math class! I aced this in high school! Now I have more time to devote to biology/ultimate frisbee/my boyfriend (etc.)" They don't do all the homework - because they already know this stuff, right? They don't study as hard for the exams. But this is college algebra, and college pre-calc, and so on. By the time they get the feedback on their first exam as a C or a D or an F, it's often too late to salvage a good course grade.
It comes up every year, multiple times, on all the SA forums: if I validate a class, should I move ahead or stay back? I say this from experience and with the benefit of data (yes, from my college, not a SA). We (all of us institutions of higher learning) are really good at figuring out what our students are ready to learn. If you take a placement exam that puts you in calc II or III, we're not just hoping you do okay - we know you can succeed. The advantages to taking a remedial course turn out to be few or none, whereas the potential costs are enormous. Contrast that with moving ahead, where there are still potential risks (but the same risk to your GPA), but also potential enormous benefits in terms of opening up different course tracks, the possibility of doing research with one of your professors because you now have the time, and additional courses that could help your service selection. Validation is a gift. Take it.
