"Besides, it seems everyone thinks that as soon as someone declines a spot, another will open up for someone who has been waitlisted or deferred, to which I have to say, I'm sorry, because schools admit a lot more ppl than they have seats for and consequently, they already expect a certain % of those admittees to accept and decline. Only when their % estimate is off do they usually start admitting extra students. Thus, each spot declined = the opening of a fraction of a new spot. At least this is from what I understand -- I could easily be wrong."
That's a good point...but here is how I see it. Let's say, Bob is trying to get into a T4 school, but has only heard back from non-ABAs so far. The T4 already sent out their auto-admits and gave them 30 days to send in a deposit. Some people sent in their deposits to reserve their spot. After the 30 days, the T4 school sends out more acceptances to fill the remainder of its seats. There will be less acceptances to go out if more people send in deposits. Bob is put on the waitlist.
By the time the schools go to their waitlists, Bob already had to put down a deposit on the non-ABA school. Even if he is pulled of the waitlist, Bob is committed to the non-ABA, because he doesn't have the money for another deposit. Bob is screwed.
Is Nicky more deserving of the spot? Of course, that's why she was accepted early and Bob wasn't. Does she have the right to send in as many deposit as she wants? Of course! I was just stating my opinion that I think it's a waste of money to send in deposits to two schools you might not even attend. It also adversely affects the plans of other hopefull law students.