While a few Elders may lurk to out people, most simply do not have the time or the motivation to do so. On the other hand, if one had suspicions already about someone, or they were outed to an elder by someone else, a bored elder might start poking around to see what evidence is out there.
But what about the majority of lurking Elders? They may just lurk for the same reason that I do. Curiosity. Im an active MS. I lurked at first to see the other side of the argument. How might a "mentally diseased apostate" try and trip me up? lol on mentally diseased part, please dont get offended.
After that, I got hooked on seeing reactions to Boe letters even before they were read in our cong. In our cong its always "oh this is a great change" But maybe its not...
Lurking here has had at least one other benefit. I have become less black and white in dealing with people. Instead of running to my elders when i figured out an aquaintance of mine was turning "apostate", I was able to ignore it with the attitude of "to each his own".
I was able to talk candidly, without judging him. It was kind of nice to already know what he was talking about when he brought up the "2 witness rule".