FuzzieAlum: In my experience, it seems that at the smaller schools who have only 3 or 4 sororites and Greek Life tends to be popular, people are buzzing more about recruitment and sadly, the sororities' stereotypes/reputations. When the student body is small and everyone knows everyone and will know you as "Kristi the XYZ", it seems very important to some girls to get the "right" house. They don't necessarily want to be Greek....they want to be popular.
Edited to add: Oh yeah, and every house seems to want the same 10/20 girls. The "it" houses know that they can not bid some girls during formal b/c those same girls will be hanging around waiting for COB. Seen it happen a million times.