... what is the hidden trading pool? Apologies for my ignorance.
I assume this is in reference to a pool of collectors who have rarities and only trade among themselves.
I recall back in the day being a bit irked by what seemed to me an elitist attitude adopted by some collectors.
But it was once explained to me that rare recordings were used as leverage to obtain other rare recordings, and if they “got out,” they would lose their value as a trading commodity.
I also recall some stating that these recordings were given by individuals close to the band and they were simply honouring requests not to share those recordings — or at least apparently not outside of an exclusive circle.