This reminds me of a nightmarish story. A couple of years back, when my boyfriend and I had just moved into our first apartment. One morning, I was taking a shower as he left to catch the bus to work. I heard the door open back up after a few minutes, so I walked out of the bathroom and asked "Sean, did you miss the bus?" as I nakedly made my way to the stairs. To my dismay, Sean had not missed the bus, and instead the FedEx guy misread the large-all-caps-red-bold-font that said PRIVATE ENTRANCE and just waltzed right on in.
I turned red. The Fedex driver turned around. He apologized as he sat the package down, and I said "Oh, it's okay." And then I realized what actually happened, and proceeded to say "I can totally see how you would think this was a public entrance, being as it's one of three doors, that all say private entrance, with their respective apartment letters..." He apologized once more, and explained that he thought that my door led to all of the apartments, to which I responded once again, "Oh, it's okay." He left promptly afterwards.
On top of that, it was a mistakenly sent package (TWC sent us two modems, made us pay to send the second back...)
I always lock the door now.
Sean always locks the door now.
I won't leave the bathroom without a towel securely in place now.