Access to field's information

Access to field's information

We are a sales organization performing In-home presentations for our leads. 
Due to company's policies, our outside sales rep are not supposed to have access to the leads phone field and email field.
We've done the obvious,  limit their access  setting the proper permissions inside the module.
This seems to be useless since they can still access this information in the lead's timeline. 
Is there a way around this?