Good point. I got distracted by just replying to your post in the context of an EU-encompassing discussion.
So far as I'm aware, the Old Jedi Order didn't track its former members. Of course, in AOTC, Jocasta Nu asserted that only twenty* Jedi had ever left the Order, so there may not have ever been more than one at a time to consider anyway.
Whether that was meant to reference Jedi who had merely "resigned" from the Order, Jedi who had fallen to the Dark Side, or both, however, isn't entirely clear. I'm personally in favor of interpreting it as Jedi who had left but had not necessarily fallen; otherwise, EU stories almost assuredly go above that number, if you have to factor in fallen Jedi like Ulic Qel-Droma, Exar Kun, Revan, Malak, and so on. I'd also prefer to interpret it as excluding any Jedi who had been exiled from the Order, such as Kreia (Arren Kae?) or the Jedi Exile.
The closest to "keeping tabs" that the Old Order came, I think, would be in making use of initiates who had not passed their trials by incorporating them into the various Service Corps: Agricultural, Medical, Educational, and Exploration. Those who had not passed their trials weren't cast out of the Order, but welcomed as Jedi who could still use the Force to do good in the galaxy - they just weren't going to continue their training at an academy and ever be Knighted. Also, as fett51 mentioned, a trilogy in The Clone Wars featured "the Citadel," a prison built at some point many years prior to the war to incarcerate fallen Jedi.
As far as I can recall, the New Jedi Order has to date (as of the time period covered in Fate of the Jedi) only ever had two former members who had not fallen to the Dark Side. Tahiri Veila had started down that path during Legacy of the Force and was redeemed, but chose not to rejoin the Order. The second is Tenel Ka Djo, who "left" the Order to become the Queen Mother of Hapes but, of course, still maintains close ties to the Order. The only other "former Jedi" I can think of at the moment during the existence of the New Order are fallen Jedi - all of whom, so far as I can recall, are also dead at this point.
So far as we know, those other groups I mentioned before didn't really have "former" members. Plo Koon "left" the Baran Do to become a Jedi Knight, so the Baran Do had no reason to track him out of concern for possible future actions. The Fallanassi and Aiing-Ti Monks are both rather insular, keeping mainly to themselves except when outsiders come to visit (and the Aiing-Ti rarely allow visitors). The Jensaarai are somewhat allied with the New Order and some have been trained by the Order, but they've been lightly explored in the EU for the most part. The Witches of Dathomir rarely leave their planet, to the best of my recollection; Teneniel Djo, mother of Tenel Ka, is one such prominent exception.
(* In Dark Lord: Rise of Darth Vader, Vader introduces himself to one Jedi as "the twenty-first.")
