Hmm. It would be possible to add some scribble on a couple of lockers, maybe one per segment. The scribble could be the last number in the tag code. That would be a hint that the lockers also need to be counted backward...
Viewing post in What did you think of the lockerroom puzzle?
Feasible even, that somebody kept forgetting which locker was theirs and doodled either the code for their locker or some other hint on it. Actually, some scribbles could even be hints about the character a locker belongs to instead of hints for the puzzle, make people want to take a look at them regardless. Just a fun idea!