Except most of the states in the south are not open primaries. Committed Socialist could vote for their Republican choice, since either Clinton or Sanders would be acceptable (pushing the socialist agenda forward).
Georgia, Alabama and Arkansas are open primaries. Trump is leading in every state in the SEC except it may be a little closer in AR.
Coming off wins in SC and NV Trump’s poll numbers can only go up in front of the SEC. I still think there is a good chance Jeff Sessions endorses Trump.