Just left a meeting with my line manager where I got a formal warning as one of the executives made a complaint. We're only allowed three of those ever (thankfully I had none) , and it'll reduce my end of year bonus.
It's not even formally the “Executives Bathroom”. It's just the closest one to them, and the only one that regularly gets cleaned/repaired/has non-transparent toilet paper.
What I think is really the case, is that one of the female executives didn't like me using the gender neutral bathroom at the same time as them. That's the only time one of them would have seen me in there.