As far as CNC lathes,the one thing that all operators should be wary of is loose jaws or broken master jaws.
We have a Mori CL-25.
We were ID chucking a fairly large part,the master jaw was cracked.
When the master jaw finaly let go,the jaw and part hit the door and knocked the door completely off the machine.
Incidents like that are rare,but should be a mental note when inspecting a machine during setup.