I have/had family members who were elders. Eventually Watchtower instructed the elders, “Stop policing the flock.” Why? Most likely lawsuits.
Before that elders followed people suspected of “wrongdoing”. For instance, one family member in the role as elder followed the theocratic ministry school conductor who was suspected of being gay into a gay bar and found him holding hands with a man. He was promptly disfellowshipped.
The same family member followed another person suspected of having an affair with his sectary and so followed him, but they could never find anything on him.
In one of Ray Franz’s books (both which I highly recommend you read if you are interested in this organization) he highlights how the Greek Branch spied on a gathering of “apostates”, and photographed who came in and left. When caught, Watchtower denied responsibility and allowed the man spying to fall on his sword for them.
It is not official Watchtower policy anymore. HOWEVER, it is still known to happen. There are many reports here of elders on stake outs and waiting outside people’s houses to see if there is wrongdoing. Most likely zealous elders who are drunk on their own “authority”.
This is an organization were informing on errant thoughts and behavior is expected, even if it breaks medical or other privacy laws. Some JWs can sometimes snoop and have no sense of boundaries.
Since you are a “bible study”, JWs view you basically as a “spiritual” child. And like any “parent” can and will snoop “for your own good”.