Ok, so obviously I know that they are meant to mask your identity from certain faction members that aren't guard dogs or higher ups. However I think I still need a lot of clarification on some of the mechanics. From what I've heard, any reputation increases or decreases are removed once you take off the disguise. So does this mean that if I go around murdering the legion with NCR armor, and I take off the armor would that mean my reputation would return to what it was before I donned the armor?

I'm trying to see if it's possible to be on good terms with both the Powder Gangers and the NCR.