It supposedly happened in Kuwait, with showers that were either used by multiple branches of the mil. or used by the AF and "tagged" by the Army guys.
I was told by a relative in the AF. Just wondered about it, since I had not heard of it before.
Not to say soldiers don't do stupid stuff now and again but it would be a very, very isolated event.
In the military somebody is in charge of everything. If one branch starts to have problems with another things tend to get placed off limits quickly.
At the very least some Senior NCO (Sergeant Major type) is going to have a few First Sergeants in for a chat. Shortly thereafter, as everybody knows, shit will roll downhill very quickly to the privates.
If the troops have enough time to come up with stuff like that then they will find other things to occupy their time. Lower ranks do not like to have their limited free time messed with and will police themselves very quickly.
The story may pass into unit legend but it sure will not be repeated.