Good question and there are devils in the details.
It is bad form to receive more than one LL and the earliest a LL can be sent out is October 1st of senior year only after a compete application has been submitted.
My son only received only one LL. However, he received firm offers of LLs from several schools.
Most coaches offer the LL with the condition that you apply EA or ED and that their school is your first/only choice.
Once my son decided on his first choice, we asked for the LL with the conditions attached. He submitted the application on September 15th and received his LL for EA on October 1st. While EA policy did permit him to continue to consider other schools, as the school had used up a LL (which is a limited resource), we notified all the other interested schools he had made a binding commitment.
It is worth noting/discussing, after our sport’s national championships in late June, our son was contacted by a number of programs. He had been diligent about sending all his academic updates to all the schools leading up to the championships, so many of the coaches had prereads done in July. We made unofficial visits in late July and had offers of LL from most of the schools in early August.
Interestingly, two of the LL offers were “exploding” LL, meaning, that if my son did not take the LL by a certain date, it would be withdrawn and offered to another athlete.
One of these two schools we were considering very seriously (it was the one where the coach originally didn’t want to recruit my son), but it was not his first choice.
Ironically the only preread that hadn’t been fully competed was from our first choice school (adcom officer who was needed to make it absolutely official was out of the office in early August). While the coach assured us everything was going to be okay, we felt we needed to hear the preread was approved by admissions. Ultimately, we turned down the LL offer from the exploding school and wait (less than 24 hours fortunately) for the LL from our first choice to become official. That was a stressful day…
So to summarize, my son did not receive multiple LLs, but we had the good fortune to be offered several. The exploding feature caused a fair amount of stress, however I can understand how/why coaches want to get their teams set, especially given the small universe of academically qualified athletes we have in our sport.
I think the reason I am so familiar with the Ivy athletic recruiting process is that we had coaches and athletic directors from 5 Ivy programs explain the process to us. The process at non-Ivy schools such as Stanford and Duke is different so that may explain some of the confusion some people might be having.
This idea of early Ivy recruiting is complete contrary to what I learned during our process (HS Class of 2015), so I think either this is a new phenomenon, or this is a new way of separating hopeful families from their financial resources (via summer camp tuitions)