Would it be a problem if a woman(in emergency) run into men restroom?

If somehow the line in women restroom so long and there’s no one/few people in men restroom and a woman who cannot ‘hold’ it anymore run into men restroom and do her business there. What do you think about that?. Would it bother you?. Can she really be arrested by the authorities?. Will you allow someone from the opposite gender get into the wrong restroom if you’re there?.