It's not about what you wear, but about how approahable you are.
The best instructor I had, was very good for a number of reasons (most not relevant to this thread). But one of the things I liked about him was that if I asked him a straight question, I got an honest answer, not a textbook one. Sometimes this would mean he'd have to tell me "I don't know", or "There's no right thing to do in that situation. You'll just have to decide with seems best, and go with it. What I would have done was..... But don't forget you always have the option of...."
But most of all he had confidence in my flying. Or at least appeared to have. That way I didn't mind telling him about my mistakes, and asking his advice. Had I not thought that he had confidence in my flying, I might have been more reluctant to discuss these things with him, in case he suddenly thought I was no longer capable of flying solo, or want to go back over areas I'd already covered.
This I suppose is why most students and PPL's don't want to discuss their mistakes. Fear of being "gounded for further training."
So instructors, always let your students feel that you have confidence in them, even if you don't! Otherwise they won't talk to you about their mistakes!
dp