I'm sure calling everything as honestly as possible can put me at a disadvantage. It has everything to do with a person's character in my opinion. Honest people are going to be honest in all situations.
When I play, I'll usually concede the close calls to my opponent, especially if I can barely get a racquet on it. I just hope that the same courtesy will be extended to me. It almost always works out. Occasionally my opponent has corrected me, or we play the point over.