How can it be proven that they didn’t vote for McDaniel? That’s my point. What happens if it is shown that a sufficient number of votes were illegal? I do have a serious question: what happens next?
The illegal votes throw the result of the election in doubt, regardless of whom the illegal voters selected (which cannot be known because of the sanctity of the ballot).
What happens next? McDaniel might contest the results, then due process according to the MS laws regarding elections would proceed. You would need to research MS law to determine what is prescribed.