Go for it! I've done it for a few years & I've always had a good time. It's a great way to lend a hand to your favorite radio station and to meet fellow 'FMU-enthusiasts. The Metropolitan Pavilion is easy to get to and you can do your record/cd shopping after or before your shift & you may be eligible for complimentary re-entry for the remainder of the weekend (if I remember correctly, unless times have changed). You can also put on your resume that you've volunteered for FMU. I know this may sound silly, but FMU has A LOT of listeners, so it's a great way to relate to prospective employers. "So you're an FMU volunteer -- I love that station! We could use a gal like you around here" so really, there are more reasons to volunteer than not.
Contact Mr. Williams post-haste:
http://www.wfmu.org/recfair/See the bottom of the flier for details.