The BATF has a long history of that kind of crap and it's a disgrace. I don't know if they still do that today -- maybe they do.
While I don't know all the details of the sting in this article, and it's possible these people are being improperly entrapped, I don't think that's likely.
For one thing, a sexual or violent crime is a much more serious matter than a technical crime like cutting a shotgun barrel less than 18". So stronger measures seem appropriate to catch these guys and put fear into others who are like them.
See my post #20.