I would strongly disagree with the idea that applying ED and not getting in helps you. the flip side of this is you are now in the regular admissions pile since you may not get to that pile until October, may at the bottom of the pile. While you may have been screened for ED, it does not mean you application was fully evaluated, letters read, review considered, etc. so you may be just starting the evaluation process late in the cycle. Additionally, with many applicants applying ED at most schools, it will not impress the adcom that you are applying to only this school. No one will care. It will not help your application. Indeed, if you make this is the only school you are applying to as major point in your application without string reasons and evidence to back if up, it could hurt your chances
The question I have is which is more important: becoming a physician or staying in the geographic area of the school? If it the former, then your logic for only applying to one school is thrown out the window. If its the later, realize many schools, might send you to distant location for various rotations, and residency as well as practice may send you across the country.
So you have to ask yourself which is more important: becoming a physician who or staying in the location. And if you answer both but I’m gonna say you havent answered the question
The thing is, you are giving general advice geared to the 99.99% of premeds who desperately want to become doctors, and are basically willing to go anywhere and do anything for the privilege. The fact that more people like that exist than there are available seats in med schools is precisely what creates the so-called "sellers' market" that allows schools to do pretty much whatever they want to applicants in the admissions process.
@Radishguy is the 0.01% exception. He is an established person with a life and a family, who would love to become a doctor if, and only if, he can do it on his terms. Sure, he is less likely to succeed than rest of us who are willing to invest countless hours and thousands of dollars applying to dozens of schools chasing our dream, but that's his call, and there is nothing inherently wrong with it. I honestly don't think being placed in the regular pool after being denied admission ED is a big deal, since it's likely a soft R at that point anyway. So what difference does it make just where in the pile the application is, after being reviewed and rejected for the early acceptance the applicant sought?
OTOH, he is EXACTLY who ED programs are designed for, so why discourage him? He has clearly articulated reasons for wanting one, and only one school. Most schools don't care about that, and don't offer an ED program to accommodate it. This one does, and it comes along with an admissions preference if he turns out to be what they are looking for. And, if not, that's fine, since he is apparently unwilling to separate from his family for 4 years, or to uproot them, in order to pursue this. That's a perfectly legit choice.
As far as rotations, many schools do not send students all over creation, but, even if this one does, that will only be for discrete blocks of time, so it's likely manageable. As far as residency, none of us knows enough about his goals to advise on whether he might have to move in 4 years, which he must realize will be a distinct possibility.
In any event, that has nothing to do with the original question, which had nothing to do with what OP surely already knows - i.e., that applying to only one school seriously limits one's odds of success. The question was whether WL was a possible decision in applying ED. And the short answer is that it doesn't matter, because if an applicant is unsuccessful ED, the odds of success later are seriously diminished, whether it's a WL or a spot in the regular pool, due to the significantly increased competition in the regular pool and the fact that the applicant was already passed over ED.