Since you had a little bit of a build up, you might have noticed right off the bat that both are marked "Men". Thing is, most people don't notice. I can't tell you how many female visitors to our office use one of these restrooms. I suppose it is a conditioned response; look up and see the sign that says "Men" and automatically enter the opposite door, without checking the sign. We try, really we do, to stop people. When we have hosted events at our office we have tried making announcements, putting up additional signage, etc. Some people just don't pay attention.
For the record, we have a lovely women's restroom, back by the kitchen. I know, I know, that is yet another little chauvinistic jab. But, it is lovely, and not industrial-looking like the metal-stalled and brightly lit men's rooms. And, in the interest of fairness, our ancillary building next door houses a mostly female workforce, where there are two women's rooms and one men's. They don't have quite the same entertainment value, but it evens things out.