I recently saw an article in my school's paper regarding fraternity rush:
http://www-tech.mit.edu/V122/N51/51rush.51n.html
There's been a falloff in numbers as the school transitions to deferred rush (was August, now September). There's also a very uneven distribution of pledges - some houses have zero, some have over 20. IFC and fraternities seem to be blaming this on "clique pledging", where a group of people will go through rush together and all join the same GLO.
This hasn't been much of an issue in the past, because rush was the first thing you did, before such groups had a chance to form. It is less of an issue, IME, for formal sorority rush, since cliques would likely get broken up among several rush groups - whereas, with fraternity rush, the existence of a clique is obvious because all the men show up together, or at the very least, are all suspiciously visiting the exact same houses.
So I'm wondering - how much of an issue is this at other schools? Would you bid Joe just to get Bill, Fred, and Tom to sign - or would you invite Susie to pref just to get Sally and Jenny to accept their pref invites? Anyone go through rush as part of a clique, and were you happy with the result?