It wasn't the same thing, but Mary did have to hide she was a hunter from everyone back home aside from those that knew it already. It was just to protect them from the darkness that being a hunter always brought with it. You saved lives, but there was always a cost to yourself and the price was always high. In a way, it was similar to Alec; in not telling people what he was, he was protecting them as well as himself in case Manticore decided to show up here.
At his comment, she smiled playfully in return. "Well, now you've gone and done it. My curiosity is peaked and that bar is set high. I expect to be seriously impressed."