Note that there is a potential issue with taking this approach. If they disable VBA when they open the file, the VBA code will never run.
An approach I have seen people use is to go about it the reverse way. By default, save the file with all the sheets in question hidden.
Then, have the VBA code verify who they are, and unhide the sheets, if appropriate.
And then have a BeforeSave event that re-hides all those particular sheet upon saving.
That way, if they disable VBA, when they open the file, those sheets in question will never be visible.