Cause if you chose GULC or NU, there's a 70% chance you'll get zero grant money, whereas with UCLA, there's only a 35% chance you'll get zero grant money (and now they have tuition revenue to plow into financial aid).
Also, LOL @ anyone who think law students, on average, are rational consumers of legal education. This is a profession for status whores. We all wish OTHERS would be scared away by price, but how many of us would actually pass up our dream school for reasons of cost.
These two statements don't really add up.
1) If pre-law kids are debt-conscious, I suspect they might take a school that is slightly lower, or similarly ranked but offering more money. Or consider that someone who only just got into GULC and would be expecting to pay sticker, probably won't get that much in the way of scholarship money from UCLA.
Alternatively, if one is out of state for UCLA, the tuition will be 50K. NW is about 47k, GULC is about 44k (correct me if I'm wrong, I'm getting these numbers off this site). Importantly, they are less than what OOS UCLA would be. So, even if UCLA gave some scholarship money, the costs might not be wildly dissimilar. That is, even if you have a 35% of getting a 10k scholarship, a 4k deduction on tuition per year from UCLA might not look as good as a GULC degree. And anyway "how many of [these students] would actually pass up [their] dream school for reasons of cost"? Especially when the cost difference is not that great.
2) If, on the other hand, pre-law kids are not rational consumers and are prestige whores, then they will take the higher ranked school and not care that there is a 70% or 35% (or whatever number you're making up) chance of scholarship money somewhere else. So, on those assumptions, few people would choose UCLA.