I could see it happening
Last year, we were upset by an inferior in-state school on their home field, so it could happen. While your fan base is superior to Ole Miss' (their best students were killed in the Civil War and the only ones left were cowards and cripples, plus generations of families hanging out together in the Grove and inbreeding, has caused their fan base to be a bunch of large-lipped, unibrowed, extra-chromosome Window Lickers), I don't think The Mississippi State University will be overconfident and looking ahead the way we were last fall.
Preseason games don't count in the standings, but they're important nonetheless, and this is an important pre-season game for us. We have to get all the kinks out and get ready for our National Championship run when we play LSU on September 12. I'm guessing, like the NFL preseason games, we'll have our starters in there just long enough to get the rust off, then put in our backups to give our bench some experience, then give the Walk-ons something to put in the Press Guide ("So-and-So, 6 yrs-Sq., contributing to the team in many ways, rushed for 150 yards and 2 touchdowns against Southern Miss").
Hope fans from both schools get to MM Roberts safe, and when the usm fans leave in the 3rd quarter they don't cause any accidents or tie-ups that'll cause fans of The Mississippi State University to sit in traffic when they leave the stadium after the game.