I believe the Jamul Toads club was formed, at least in concept, when Coach Bob Larsen ("CBL") was coaching at Monte Vista High School in the 1960s. Several of his runners (legendary in those parts) either lived in the rural area called Jamul or frequently ran there. I attended MVHS in the 70s, and ran CC and track there, later training under CBL at Grossmont College. It was a kind of joke - becuase Jamul was the "sticks." Larsen had such a huge impact on the sport in San Diego - so many athletes over multiple generations spawned from his coaching methods, and there are several coaches and students of coaches who could trace their knowledge and dedication back to CBL.
It was big thing to be a "Toad" for the distance runners in San Diego - even though there was really no formal membership that I recall - other than someone with some "rank" would give a good runner a singlet. Once you had that singlet, you were a "Toad" - others can correct me if I'm wrong here. Most of the Toads that became nationally known ran for Larson and Grossmont College, though many other very impressive local runners knew CBL, and ran for the club, most principal of those in my mind was Dale Fleet, who was the de facto leader in the late 70s. Of course, the national championship team boasted some amazing atheletes - runners who had great talent that was made even greater by CBL - Terry Cotton, Ed Mendoza, Kirk Pfeffer, Tom Lux (all Grossmont athletes); Dale, Dave Harper and Mike Breen (all Clairemont High - a great era for that school), and Thom Hunt - who ran with the Toads upon occassion (and with Cotton at UA). Of course, the list is much longer.
I'm pretty sure that a past Toad can pass, at his/her discretion, a singlet to a child. I have a sense Mac Fleet was a Toad while he was still a twinkle in his Daddy's eye.