Hell no! I don't pick my nose in public places. I guess the reason for this is that it has never be part of my behavior, neither has it be my habit. I have always been so conscious what I do in public. This consciousness has been there right from when I was kid and it has extended to my adulthood age.
I've always know that habit like this is so irritating, especially if done involuntary in the midst of people. They might be so sick to the stomach with person's behavior that they would wish to remain aloof from him/her.
Unfortunately, apart from its irritating aspects, it is not healthy for anybody to be picking his/her nose, whether done publicly or on the inside. Habit like this happens to be the means disease-causing microorganisms such as bacteria, virus, fungi, etc, get into the body. No wonder people fall ill so easily, which I presume is caused by the habit of picking one's nose.