Yes. Grades are basically useless as a measure of a student. I'm a second-career teacher, and can tell you that teachers in the same grade, and the same department, of the same school, will have wildly different grade distributions. Now try to compare grades between students who come from different schools...or even states...or heck, even countries...and it's simply impossible.
When the revolution comes they'll have standard-based grading, but as it is now, at my low-income school I will basically give an "A" to every student who puts in a semi-decent amount of work (no homework, I just mean they pay attention in class) and has never had a traumatic brain injury. I've also taught at high-income schools, where cheating is rampant and giving an "F" on an assignment 1st period means an angry letter to the principal from the parent by 3rd period.