It would be interesting to see how this would be handled in the European Union. It's almost certain that it would have been more work for the HR department than in the US.
If you ignore the guidance they'll start issuing warnings. Those warnings are kept on file to help with potential employment tribunal cases.
In the UK: after two verbal warnings and one written warning you'll be fired. Or sooner, if your behavior meets the gross professional misconduct level. (You punch someone, for example.)