I found this article.
The NCAA’s guide to how the 68 teams are chosen, seeded and bracketed for the Division I men's basketball tournament every season.
www.ncaa.com
It specifically says "
the committee shall not place teams seeded on the first four lines at a potential “home-crowd disadvantage” in the first round." I'm guessing that eliminates Iowa State from Des Moines, unless they say that Des Moines is already a home court for Marquette, but I doubt thats true.
Another 3 seed that could get Des Moines is Gonzaga. Denver and Sacramento will likely be full before they get a spot.
Another line is this: "
A team may be moved up or down one (or in extraordinary circumstances) two lines from its true seed line (e.g., from the 13 seed line to the 12 seed line; or from a 12 seed line to a 13 seed line) when it is placed in the bracket if necessary to meet the principles."
So based on that, if Iowa State was a 6 seed and theoretically should be in Des Moines, they would move them to a 5 or a 7 seed to accomodate.
So here is a hypothetical.
Baylor wins the Big 12 and becomes a 2 seed. Texas looses game 1 and becomes a 3 seed. Kansas State is a 3 seed. Kansas is a 1 seed. Lets say Kansas is in the Midwest, Baylor gets the West, Texas gets the South and Kansas State gets the East.
Iowa State can't be in the South or East because they can't match up with Texas or Kansas State in round 2.
Iowa State can't be in the West because they played Baylor 3 times and can't play them again until the elite 8.
Iowa State likely can't be in the Midwest as a 6 seed bec ause it would be a potential home-crowd disadvantage.
Iowa State likely either moves up to the 5 seed or down to a 7 seed.