I have a Peter Pugger 9 and we switched from stoneware a few months back so I cleaned it up from top to bottom to get the old stoneware out and it is pitted. We have mostly used Seattle Potteries Vashon White but I did make a house white stoneware and I assume that's the culprit, I had read about the porcelain issue and was prepared for it to happen with the new stuff but was surprised to see it with the stoneware.
Does it matter a great deal? I have been using it a bit lately and seems to work fine. I am assuming at some point it might be an issue with vacuum? Did they mention the issues that one would have with the pitting?
Well the one thing I will add John is that doctors can both be wrong and difficult to deal with. Egos and plain misinformation can get in the way of truly getting to the bottom of a health issue and allowing a person to make the final decisions after reviewing all the options. In this case I can see many doctors simply telling Sylvia to cease her clay work because clay means dust, dust is bad, end of discussion. No one can argue that's wrong in that it completely removes the danger clay presents to her condition. At the end of the day it may be exactly what Sylvia decides to do but there may some shades of grey here for her to explore as well.
The Internet does provide a way to thoroughly research this condition and get a wide range of opinions and information, providing of course the person understands how to filter through it all and not rely on ad hoc hypotheses. Before the Internet we used to spend time in the library working our way through the card catalog. The information was likely more accurate because of the complexity of a book ending up on a shelf but information was also more sparse for the same reason.