The universities I've worked for and attended will not accept Wikipedia as a reliable source because the information is not peer reviewed and anyone can add content. Students are therefore discouraged from using it for anything other than a quick search to give them an idea of information that *MAY* be available on a topic. If it shows up in an actual assignment, students are graded accordingly.
Part of being a student, particularly at University level, is being able to critically evaluate sources, and while peer reviewed journals are far from objective in what they may publish, at least most attempt to ensure the work is of a particular quality and accuracy.