@Muwahaha,
Actually a company party with alchol involved is not asking for trouble. We are all adults and should be able to handle our alcohol. This is a professional job - it is not a first time job. It is a job where you are required a college degree and x number of years experience. It is not a job for children. The expectations of the job is to be professional.
And yes you can tell by one response that a person is immature. I have been in management for over 10 years - I have always been rated most highly in my management skills and dealing with employees. And I am not ambiguous to the work performed as I have mentioned the performance is good, but not stellar. Part of the job responsibilities is dealing with others for example other groups both peers and those at higher levels. This person is not meeting job expectations by his lack of professionalism.
How can some one represent the company positively if they over drink and steal a Holiday decoration? How do they represent the company positively if they piss and moan in front of the group, call in sick and leave early because they are dissatisifed with a raise that is above the target range?
And of course he has been repeatedly spoken regarding his behaviour at the party - he agreed his behaviour was childish and he apoligised and said it would not occur again. He has been repeatedly spoken to about his lack of professionalism.