The guidance I have received is that it is not difficult to pick up tickets for round 1 (though pending our location demand for our unique session obviously could be off the charts). I was told to pick up cheapest tix on stubhub or literally outside stadium and, if we are not the first game, there will be ample opportunity to relocate to better seats as losing team fans of earlier games vacate. This from a trusted ND alum who has done this before.
I just remember freaking out about getting 1996 Rose Bowl tickets and then finding myself trying to sell extras minutes before kickoff. Admittedly, wherever we play will have fewer seats than the Rose Bowl...
If we are in Milwaukee, Indy or Buffalo, I will happily accept assistance obtaining tickets from any kind sponsor.