Seriously... what does it matter? Nine times out of ten, the hair is about the same. My ex and I kind of got into a groove of using his at his place and mine at my place. They both get the job done, and as long as you're careful about frequently rinsing out the blades, they don't mess up the next person's shave.

I think you're more bugged about the invasion into your personal belongings without asking than you are about it being a man's razor used by a woman.