What steps can US undergraduates take to reduce the frequency and severity of assignment of unearned grades, as from grade inflation and cheating? The book Academically Adrift, by two University of Chicago professors, is one salient source. The following refers to collegiate institutions in the United States. 

Reports, including from professors like Rebecca Schuman, show: 


Professors, especially adjunct faculty members, often inflate grades with the goal of bribing students to leave favorable anonymous reviews. Adjuncts' jobs often hinge on these reviews, so pressure is high. 
60-90% of undergraduates probably cheat often. 


According to The CUNY-Wide Conference on Academic Integrity, a quote-worthy report concluded that "9 in 10 students [actually 86%, according to CampusTechnology.com] admit to cheating in college and the students who do report cheating indicate that they cheat frequently using a variety of techniques and that they suspect faculty do the same" (however, the original source seems to be unavailable). 
According to the Stanford Academic Cheating Fact Sheet, "73% of all test takers, including prospective graduate students and teachers agree that most students do cheat at some point."



Large segments of both groups want students to have unearned grades. This is likely to mean:


Many students pursue unearned grades by various means, not limited to cheating. According to some professors, these include:


simply begging professors for unearned grades
escalating demands for unearned grades to institutional administrators

There is a strong incentive for students and professors to collude so that students get unearned grades. This can occur via:


acceding to demands for unearned grades
assigning grades that are disproportionate to learning and/or work (by making courses easy to begin with and/or by raising grades that would have been lower according to rubrics or other policies)
inadequately testing for plagiarism (Anecdotally, I have seen this on assignments submitted to Canvas, a platform in which all students can view one another's work. Canvas also calculates average scores for all assignments, so I can calculate average grades for the course as a whole.)
failing to adequately monitor exams, so that students can easily do searches under tables (I have seen this)
allowing students to leave exam rooms (I have seen this)



Possible steps to combat the problem might include:


ascertaining causes of grade inflation
determining whether academic misconduct is a factor, and whether implicitly allowing cheating is a common method for grade inflation, given that it confers plausible deniability to professors, unlike other methods which might require suspicious changes to rubrics or violations of them
seeking allies among faculty or even students
seeking media coverage
seeking involvement from citizens outside the institution, especially in the cases of publicly funded colleges, which have specific standards of accountability to the public


Where have such measures, or others, been attempted, and what tactical and strategic indicators can be gleaned?
Grade inflation is not happening because of academic misconduct.  That has zero to do with it.  Most of us are surprisingly good at spotting plagiarism and we give out a depressing number of zeros for that and other forms of misconduct.  Trust me, very few of those students are contributing to inflation.

Grade inflation is a long-term slow trend.  Most instructors try to grade "about like" their colleagues in the department.  But few of us want to seem unfair, so we err on the side of being a bit generous. Over time, you get inflation.

But go for it.  If you came to me, pleading for a tougher curve and a lower grade, you'd definitely be my first.  I would certainly remember you.