Lock Reports From adding columns?

You can set a setting on that field to make it not usable on reports. There's a checkbox for that.

Then nobody will be able to add that field to any reports. But they still have full access in terms of permissions to have the benefit of that field in lock ups for example.

But then you might come back and say well there are certain people who are at a higher level and do you need to see these Employee numbers.

So then you can make a mirror Field by formula of that field and restrict that field by rule permissions at the field level.