Digger: The University of Idaho lifted a similar ban a while back, and as far as I can see, it hasn't had an adverse effect on the campus. As far as mixed messages are concerned, I don't think it sends one.
Sara: Making alcohol available on campus no more encourages underage drinking than selling beer at Applebee's does - the presence of underage people doesn't mean we're encouraging them to drink. And I don't know how anyone can make it through a fundraiser without a drink or two. I think it's a good idea, especially since the place where most underage folk do their drinking is outside of bars with their buddies that bring home a bunch of beer. If their buddies are out at the bar, they won't be bringing home booze for their underage cohorts. Or at least not as much.
DFO: It's a shame that booze is needed to oil the skids for raising money on a college campus. But it's also a reality. A little mind-altering here, and a fatter contribution there. A good argument was made in the "comments" section that almost all college campuses are wet anyway. Another good argument was made that it sends a mixed message to colleges, like WSU, which has had student booze problems. Me? A glass of wine at a public event is usually my limit. So, it wouldn't have a big impact.