@alice Master Locks are compliance locks. For when you are legally mandated to lock something up but do not want to.
Then you have locks that look right to any cop, but you can pick, shim, bump, decode, whatever you feel like if you lost the key or combination.
As an example, they are perfect for school lockers. If kid can't open them, dad will figure it out. But nothing really of value behind, just locked against kids accidentally opening the wrong one and making a mess of everything.