Read-Only Searches allow an employee to open and view search results, but not edit.
If you give Access to Customer and Customer Search an employee can edit customers. If you give Access to Customer Search they cannot open the Customer card to view, unless you turn on Read-Only Searches, then, they can then view the Customer card.
Go to Employee Pref and check Read-Only Searches. Then, give Access to a Search but not the tool itself, so give access to Customer Search but not Customer tool itself.