I think the WTS is on weak ground if another Witness in, say in a medical or legal matter, broke professional confidentiality in order to snitch on you to your congregation via religious contacts.
While silently "encouraging" the extra congregational snitching, I'm sure the WTS will let the snitcher hang out to dry alone if he or she is found out. So you have to show that your local elders had to be contacted with the damning information by help from the WTS and there is simply no way for the snitch to pass that information to your local congregation in any other way.
In fact, I wouldn't be surprised if the WTS will only limit themselves to giving the snitch the phone number of the PO so he or her can call the information in giving the appearance that the WTS had no active participation.
Yep, that's my guess. LOL Well, it was a good mental excersize.