How to hide rates in Summary Report for specific system users?

To hide billing information in Summary Report for some System User, you should do the following:

1. Go to System → Roles and create (or change existing) Role with Permissions for Statistics / Summary Report: "Execute".
2. Disable Statistics / xDRs List for this Role, because xDRs List always contain Rates.
3. Then go to System → Users and apply this Role for respective Users.