That is why you need to take 5 locks with you. One for the locker you are actually using and two on either side.I've read somewhere that this has to do with psychology. Happens to me all the time in empty locker rooms. Either I'm changing and someone "parks" himself right next to me, or I return from my workout and notice that the locker right next to mine also has a lock on it despite literary every other locker being available. Sometimes there's three locks in a row when I return