I never really thought about putting a lock on our fifth wheel until this year when I started seeing a lot of stories about stolen RV's. How long have you been locking your king pin?
I have a home storage garage...so I don't use the lock there. But I like to put it on when camping since it is orange and has an orange ribbon. The ribbon helps identify the pin box for safety reasons when walking or driving around it. Also, help keep the dust and grit off the greased pin when camping in a dusty area.