Yesterday, during the 1 hour I was at the gym, someone forced the lock and got into my locker. When I was done showering I came back to my locker and opened my combination lock as normal, and opened the locker to discover that everything was messed up and rearranged, with my wallet out and on top of my pants. Luckily, nothing was missing. (Not even my phone!) I took a closer look at the Master combination lock and saw that there was significant damages to the outside of it. Interestingly, whatever tool the thief used to force open the lock, left the lock in a usable state. They were able to lock it again when they were done rifling through my stuff, and I was able to open the lock with the combination.
So my question for this community is: what is the best type of lock to use on the lockers in a typical gym? Clearly the Master combination lock is vulnerable (although the version I had was slightly smaller than a full sized combo lock). Do the people here use anything in particular to guard against tool-equipped gym thieves?