I'm almost certain if a woman did it, you wouldn't be nearly this rattled. Because women are seen as maternal, caretakers. A man does it? Bring out your torches and pitchforks! He's clearly up to something sinister.
I know now you think my occupation brands me as being completely incapable of being responsible or heaven forbid - paternal, but perhaps think maybe they want a place where they can have the illusion they're living by themselves. My flat is large enough to where it's like having five separate apartments in one building.
Clearly you missed the last part where I said "so long as you keep your head about you", which means I expect them to be responsible, not to mention respectful.