I can see how someone might find this useful. It'd be a way to see behind the curtain, essentially, because I know a lot of members don't like coming to Staff about everything. And we don't see every interaction. However, I feel like doing this would only validate their fear of coming to Staff about issues. How can you trust your staff, if they are blindsiding you and going undercover to see who the 'problem' members are? This feels like a way of digging up dirt when there might not be any and can be the victim of massive amounts of human error. I know sometimes it's hard being a staff member and trying to figure out what's going on behind closed doors (dms), but until someone comes to you or you see a problem in the general chat- it shouldn't be something you go looking for.
I think some healthy alternatives would be: checking in with members if you feel there might be a problem- open the door for them to talk to you. If people are being shitty to new members/guests in the general chat- make it clear that this type of behavior will not be tolerated. Members aren't coming to you for plots/threads because you're staff- go to them with plot ideas.
So in answer to both questions in the first post: No, I have not and I have no intention of doing this.