There was a guy that sold pen materials about 10-12 years ago and was difficult to get in touch with after orders. He was banned from advertising in one magazine, or it could have been here, if I remember correctly, but he did pop up with a different name a couple of times.
That said, there is/was a problem that happened on two of three occasions in which there was a misunderstanding and people would pile on. Jeff and one or two of the moderators were excellent in controlling this "pilling on". When one guy started his laser inlays, a misunderstanding took place and after sorting it out (fairy simply) that laser inlay company became a good resource for inlays, and that is still into existence today with a good reputation.
There are certain pen makers here that sell professionally and do not post picts because people will copy. For some pen makers, copy is the greatest form of flattery. However, sometimes the blank designs are copied commercially, diminishing the value of the original. That has happened here.
There are a number of ways this happens, but in the end, Jeff and his crew have been excellent in dealing with abuse and bringing about civility here.