WARNING! A man using a ladies restroom can be arrested for many things including trespassing to flashing and worse.
I made the mistake of using what I thought was the only restroom in a gas station convenience store in Arizona and one of the women attendant's had the other woman call the police. I waited patiently for the police to show up, waited while he asked them what happened and then I got a chance to explain my actions.
I had to pee like a race horse and there was only one restroom. There were two doors one of which I thought was a door to the outside and the other door, to the right, was obviously the restroom door as it had a woman's sign just to the right and a mens sign just to its left; the sign over the "outside" door said "Restroom" not Restrooms.
I told the policeman that the men's and women's signs should have been mounted directly on the door at the very least. He let me go without even taking my name but told me that if a little girl had gone into or had been in the womens restroom while I was in there I could have been arrested for indecent exposure and trespassing at the very least.
Don't go into the women's restroom if you are male. | 
