Course evaluations are affected to a large degree by expectations that students have going into the course. But, I wouldn't confine the blame to irresponsible advising. If advisors are telling students that courses in your department are an easy A, they are probably (and unfortunately) just giving voice to widely-held attitudes regarding your discipline. These attitudes are probably reinforced in subtle and not-so-subtle ways in popular culture, by parents, by faculty in other disciplines, and possibly even by faculty in your own department who teach courses that actually are an easy A.
I'm a faculty member in one of the social sciences (albeit, not the one in which our basketball team is advised to major.) I've heard faculty in other divisions refer to the Social Sciences vs. the Actual Sciences. I've heard them call my discipline "soft" and tell students who are struggling in the natural sciences to try my discipline because it's less rigorous and much easier.
I've had students tell me that their parents don't want them to major in my discipline because it's bogus or wishy-washy. I also know that a few of the courses in my department ARE an easy A.
I'm in an odd position. Because of the courses I teach, I've had the opportunity to benefit and to suffer from expectations about my courses. I benefit in a math course I teach that is required for the major in my discipline. The grade distribution in this class is consistently low and the course evaluations are consistently very positive. I know that students come into this class expecting to work hard, but with very low expectations regarding their performance (e.g., "I just want to pass it this time, I want to live.") which are often met or even exceeded.
I suffer in another course--in a topic area in my social science in which the grade distribution is a little higher than in the math class, and the course evaluations are worse (e.g., "The tests are too hard. "Too much science," and "Too much theory.") The evaluations are generally positive, with the occasional "greatest class ever," but students are resentful of the same degree of rigor required in my more positively evaluated math course. I know that this is at least partly due to a mismatch between expectations and reality, because I also get comments like, "You have to take the class seriously," and "I wasn't expecting this class to kick my ass."
How do I deal with this? I try to adjust expectations on the first day of class. I talk about what I expect and about the danger of underestimating the course. I mention that not taking the course seriously enough has ruined more than one 4.0 GPA. And, I consider the evaluations of my topic-area class a badge of honor. I'm pleased when a physics major tells me that the course was a lot harder than she thought it would be. It is my mission to demonstrate to students that my discipline is fascinating and difficult, that it isn't bogus or wishy-washy, but rather that it is fully as rigorous and worthy of respect and effort as chemistry or mathematics. So, my advice to everyone is, keep doing what you're doing in the classroom, and be PROUD of those evaluations.