Yes, this is one for class M will get a standby by upgrade into the first class of any the flight into Delta. I do experiencing for use fly by Delta for us into long time. Well, Seiple and talk ya later!
If price is a consideration and the deciding factor as it is in this case, an M fare is not what they are looking for. I don't think they care about upgrading to First... they just want to get to Phoenix cheaply and a Delta M fare isn't going to do it for them.