Mail in ballots are an open invitation to fraud, they should be eliminated.
Actually, I believe that any request from a voter for an absentee ballot, should be done in person, with ID. The one exception should be the military.
The original reason for a request for an absentee ballot was so that a voter who would out of town on election day, would not be disenfranchised. This also covered anyone who was tied up with a vital job, that would not allow them to vote in person.