How do the students vote?

[question everything]

Now that the elections are over I wonder:

A friend of mine, from Chicago, said that her son, who is in college in what was one of the "battle ground" state, chose to register at his dorm because he wanted his Obama vote to count more in that battle ground state than in Chicago. His mother, who checked the family registration online and saw his name, wondered of whether he could have chosen to also vote absentee in Illinois and whether anyone could have caught it.

A letter in the local paper today told about a student who is studying outside of Minnesota, but he, and his parents, made sure that he got a Minnesota absentee ballot so that he could vote for Franken. He procrastinated and sent his ballot on election day with a same-day delivery.

Thus, I wonder whether, in theory, students can, and perhaps do, vote twice. Absentee in their home state and in person where they go to college.