If I'm not mistaken, tickets for the BE tournament are distributed somewhat evenly between the member schools and then sold in strips. So if you're coming from Creighton or Xavier or wherever, you cant just buy individual tix, you have to buy a ticket to every game of the tourney. After the set asides for partners and sponsors, that's an average of roughly 1,500 tix per school. Not a high bar to get over. Highly doubt the league will have any trouble selling all the tix.
Attendance is another story, but it always is. Anyone who's gone to the early rounds of the tourney knows that the place is never full because if your school played in the afternoon session and you didn't sell your seats to the evening session, the seats are empty. As the tournament goes on and teams get knocked out, many of the tix allotted to the knocked out schools go on Stub Hub and yes, in the past UConn and Cuse fans would gobble them up a) because there are so many alums in NYC and b) because their teams advanced. So it will really depend on who advances. If Creighton goes deep in the tournament, yeah, their fans wont be buying tix from Seton Hall fans in bulk. But if its any of the east Coast teams, I think those tix will get sold just the same as always. And I wouldn't sell the Midwest teams short just yet. if I remember correctly Marquette brings a pretty sizeable contingent every year. And Creighton averages 17,000 fans a game for God's sake....you mean to tell me a bunch of those people aren't hopping a plane (shorter than the drive from Syracuse, btw) to come to the big city?