I was reading and found that the security sleeve around a door knob will "protects the lock from stillson attack".
That leads me to the question, what exactly is the "stillson attack"?
The free spinning collar on your knob prevents someone with a large pipe wrench from grabbing onto and over torquing the knob. I believe this is what this attack is called in Australia. But let's not talk any more about lock attacks or bypasses or destructive entry as it is not allowed in the public forums.
Have a nice weekend