Here's something from the Masonic Information Center which addresses that. Masons certainly don't make a secret of the fact that they are members of the fraternity. We wear rings, lapel pins, and tie clasps with Masonic emblems like the Square and Compasses, the best known of Masonic signs which, logically, recall the fraternity's early symbolic roots in stonemasonry. Masonic buildings are clearly marked, and are usually listed in the phone book.
Many lodges have answering machines which give the upcoming lodge activities.
But there are some Masonic secrets, and they fall into two categories. We keep those private for obvious reasons. It is not at all unknown for unscrupulous people to try to pass themselves off as Masons in order to get assistance under false pretenses. They are secrets because they literally can't be talked about, can't be put into words. They are the changes that happen to a man when he really accepts responsibility for his own life and, at the same time, truly decides that his real happiness is helping others.