I've actually been on the receiving end of this. I frequently walk around nude, in my lingerie, or in my pjs when im home. Often, my windows are open because frankly i don't care if I'm seen or not. I know that if someone does catch me then they're in for a treat.
So one day, i came home from an event and it was night time. I had my blinds open and i started getting undressed out of my dress and into my birthday suit. And after i slipped off my dress, I turned toward the window coincidentally and saw someone staring at me from across the street. I got startled at first but then realized they were checking me out.
And when I noticed them, they turned away and started walking along lol