I know of it but I’ve not put any effort in to specific practice.

My personal opinion is that most communication between anyone contains manipulation, even if they aren’t doing it consciously, it’s an intrinsic part of how we deal with each other.

The difference is that i don’t have much of a natural instinct for it, i have to practice and be much more intentional, which brings benefits and drawbacks.

I find that a lot of people in general can be manipulated in similar ways (I’m no exception to this) but techniques vary by culture, upbringing, experience, context etc, i don’t like to do it , however, for the reason stated a bit further down.

Identifying which markers work for which people is a a lot of the battle initially.

Unfair is relative and heavily context dependent but in some circumstances yeah it can feel a bit like a cheat, what I’ve found over time is that I’d be cheating myself just as much as anyone else, my goal in general was/is better communication and understanding, if I’m intentionally manipulating outside the norms then the interaction is tainted in terms of learning natural communications patterns.

If they are intentionally manipulating outside of the norms then that’s significantly more interesting and useful for gaining samples from uncommon behaviours.