We don't want to get into the business of figuring out why people are where they are.
As a member of the military, for instance, I chose to register in the town where I rented an apartment, rather than vote absentee in the town where my parents lived. (That's still technically my home of record, though - and probably will be until I leave, unless I buy a house.)
I should be very annoyed if my home state said, "We don't care that you're living here at least 3 years. You can't vote here." I do pay State taxes.
>As a member of the military, for instance,<
Being in the military puts you in a whole different category, with different rules, than does your being a student at a college or university. In the latter case, in most instances you are still dependent on your parents for tuition and for much of your living expenses. If you are in the military, you are responsible for yourself.
I think the county should get hold of the voter roles, and slap local taxes on every person who claims to be a permanent resident.
They should also confiscate their drivers licenses if they are from another state, because it is illegal to have a drivers licence from another state if you live in Virginia.