74 CHAPTER 3 More about locks and ways to low tech hack them somewhere on the back of the lock. It can even appear to be an accidental scratch. This won't stop the bad guy from taking your lock. But if you suspect that something like this has happened to you, you could probably quickly find out that the lock now securing your locker is not your lock. In this scenario, where we're at a gym, there are a number of other things you could do to become a little tougher target. For years, when I was going to a local gym, I would use a key lock that was also a key retention lock similar to the one shown in Figure 3.5 but not as big. I did that for the same reason that I described what I like about the key retention lock earlier in the chapter. If that key was on the little wrist strap on my arm, I knew that the lock was locked somewhere. It could not be taken out of the lock if the lock was still (opened) unlocked. Many times when going to that same gym I would see locks of the type shown in Figure 3.13 on several lockers left unlocked. If you think about it, unless the locker was empty and the per- son went home and forgot the lock, it should never be on the locker unlocked unless you are standing there. Those people simply walked away and forgot to lock the lock. With the key retention lock, that can't happen. In most cases the key retention lock will also look considerably different from the majority of the locks in the gym. Most will look like the lock in Figure 3.13. If your lock looks different from everybody