when i was a CS major i found that girls got preferential treatment...one of the best looking ones could hardly program, hardly understand what a class was, barely seemed to grasp simple concepts...yet made it all the way through senior year with B's and better grades...
The only thing was she was the 1 of the 3 girls in the program and by far the hottest...and it was clear a lot of guys drooled over her (myself included)...so it kinda became clear almost that she might have been "encouraged" to stick around and keep the boys distracted at times...
but anyways subject at hand...it does sound like something wrong is going on, i say let the school paper know, let them investigate, and if an article gets written up and theres really something going on then the dean and others will have to take notice