Maybe it's easier to use a datamangement tool for this like Vault.
Agreed. If you're trying to prevent users from working on files that other users may be actively working on, then your best bet would be to go on and grab Vault so that you can incorporate a nice check in / check out into your work flow.
If that isn't your goal, perhaps you can explain in a bit (or a lot) more detail, about what you're trying to do, and why.
I agree that vault would solve the issue. However, the company has not yet installed Vault and the department that has the user issue are not too keen on using Vault anyway. I think they have solved the problem by sacking the user anyway