Generally speaking, there are 2 definitions of a "Master Set". One is the hobby-wide usage of the term, and the other is the term used here (and unfortunately, they differ).
Master Set - Term used hobby-wide for decades - 1 copy of every card published for that product release (including errors, corrections, variants, and inserts/parallels).
Master Set - term used here - 1 copy of each card within the set (not within the release). As an example, one can have a master set of 2019 Topps baseball base set (without having any inserts at all) by having all of the SPs and SSPs. The site's "master set" does not take into account all the cards issued within a product, but only with the set itself.
The site's term was introduced (fairly recently, within the past 2 years) as way to help the err/cor/var collectors know the total number of cards available for the set while allowing the collectors who only wanted 1 of each card to be able to compile a "basic set' in that style.
As far as Bob (or anyone else) being allowed to publish a list of known "errors" (most usually print flaws), there is nothing stating that forum posts cannot include these. Cards missing ink, have random ink spots, mis-cut, blank front or back, and wrong backs are all examples of printing glitches/errors that are not listable here. There's nothing saying they cannot be discussed, or even shown in a forum post. But they cannot be listed, and the idea of listing them should not and will not be entertained. Continued pushing for listing these items here will be considered trolling, and will not be tolerated.
-- Dan --
Note: Please see my profile for more info regarding trading (section updated 3/4/2024). I have added a large portion of my inventory to the site, and currently have trading turned on (details are in my profile).