I can assure you that you wouldn't want to be sitting in the defense chair if you had caused someone the loss of his/her job because you told his/her boss that she/he had been smoking dope on the job and then failed to provide solid evidence to the fact.
Let's see, defamation of character, slander, loss of wages . . . I'm not a lawyer or portray one on TV, but I sure as heck wouldn't put myself in that position.
Old saying down here in the south, "Don't let ya mouth write a check ya butt (usually another word) can't cover."
The prudent method would be to contact PADI Q/A, in this manner the complaintant remains annonymous.
the K