At our state clinic the now departed NC Asst Commissioner for Officiating briefly touched on it during the power point presentation. When the slide popped up, he said "If you see these, leave them alone", and that's all that was said.
I agree, it is unlike the Fed to do this and not put it in writing.
Also I've seen a source that the "pacifier" style mouthpiece from Battle was also declared illegal but it was not covered in our presentation and I've seen nothing official from the Fed nor the state office.
I'd say let's stop worrying so much about carpet bombing us with marketing e-mails and get back to doing more at the basic fundamental essential information level. But that's just me being, well, you know......