After all the hype and concern, going on for years now, I've yet to see a facility with multiple stalls go co-gender. Only ever the ones that are stand-alone individual rooms with locking doors and with that type, there's no danger of anyone of any kind walking in.
In the ones that the OP is posting about there could definitely be someone waiting for you to come out of your "room" since those individual bathrooms are set in a common room that houses sinks.
I would say those kinds of restrooms are even worse for women who are apprehensive about sharing with the opposite sex because with open stall concept you have an auditory hint and maybe a visual of anyone entering the bathroom. Coming out of an actual room you don't.
I'm sure for many women that isn't an issue, but there are those who have their reasons to have issues. There's no need to belittle their concerns. Maybe you aren't trying to but your post comes across as if you are telling the pp she has no reason to bring her dh in with her. You have no idea if she has no reason.