I've been teaching from 2002 to the present, and I have a number of colleagues who are or were faculty at various institutions. Other than West Point and USAFA, there is a consistent and significant minority at every public institution that seems more interested in partying than in gaining a real education and putting forth the real efforts needed to succeed in introductory STEM courses.
If by checks and balances, you mean some unbiased assessment whether a prof's graded events represent a level of rigor much more difficult than the learning objectives of the course when there is a high level of students failing or complaining, then I would completely agree. However, I've never seen this. Instead, profs are pressured to due whatever necessary to ensure high student satisfaction and high passing rates.
At one institution, I was shocked at the first department faculty meeting. A junior faculty member asked if his tenure and promotion potential would be harmed if he failed two graduate students who had completed 0% and 20% (respectively) of the required work in a summer research course. The response so pressured this faculty member that he compromised his values and both students were given Bs in the course. I've seen this situation play out many times in various ways, usually in intro courses, and with faculty threatened with various negative job factors if they don't make students happy when the only way to do that is to pass students who have not demonstrated competence in the learning objectives.
I too believe that a stick and carrot approach is necessary. But an increasing number of institutions no longer allow faculty to use the stick for students who refuse to meet course requirements.
This (
http://wmbriggs.com/post/2415/ ) is the kind of thing I am talking about, but there are probably 100 cases that don't make the press for every one that does.