That came up when he was doing Mr. Mercedes. He didn't want any of us doing research about bombs, explosives, etc. and that extends down to ordering books, going to the library, etc. It didn't occur to us to notify any authorities but then, which authorities do you go to? It would have been easy enough to defend but we really didn't want any of them knocking on our doors and confiscating computers and then having to go through the legal hoops to get them back after proving it was research for a book. I'm trying to remember but it's not coming to me who he went to for advice.
I have to say, especially on the research about the fertilizer plants, that I thought long and hard about what I was doing. Using the library computers were a great temptation. That shiz is taken very seriously. I think the same about any research into pedophilia or the like.