Bootleg Test Tone Collectors?

I thought I'd seen it all until I heard about collectors that pass around bootlegged copies of the test tones and bias pads from all genres of artists and albums. From an article in MOJO this month: "Sorting their collections by "tones at head" or "tones on tail", these fanatics derive pleasure from being able to identify different studios via the quality of the oscillators. Some collectors even listen for "rocks" in bias pads and point to faulty tape alignment as an indicator of an album's flawed sound." Wow. What's next? Collecting tape "silence" between tracks? -LC