I really appreciate the college students who have time to help teams, but I have to agree that no commitments should be made that might interfere with school. Students, parents and scholarship sponsors are paying for you to concentrate on a degree, and deserve you holding up your part of the bargain. If you can volunteer without losing sight of priorities, great. Just don't make promises that you shouldn't keep.
That being said, I understand that things get in the way of schoolwork. FIRST is a lot better reason than mine or many students' to go on academic probation
. (Note: I also made the good Dean's list while at MTU)
Edit: My wife pointed out that priorities apply to all mentors. Jobs and families have to come first for everyone.