I was at the game yesterday with two friends and we had also attended the football game against IU in November. And we were all noting how IU brought, aside from its entire marching band, perhaps 100 other fans to the football game, very much a pathetic UConn-like showing, but had about 2000 fans at the RAC. IU is probably alone among the B1G schools in having a fan base that is much more tuned in to basketball than football and it really showed "on the Banks" this year.
But as for the sell out, I think the announced sell out applied to public sale only, not to the students. And I didn't see that many empties, given the performance of the team lately, as I would have expected, aside from the student section.