Good-Person
Captain Junkie
I have not fired anyone because of misconduct, but this is something that is popular with my boss. I mean he is too good as spotting the right time to send someone parking once he notices that you are not serious with the role that you've been assigned to do at the workplace.
There are many companies that have a warning system. However, I think that warnings should be issued in case of severe violations only. As far as code of conduct is concerned, employees should be aware of what they need to do and what they are required to avoid. This makes things pretty easy for many employees.