How do I create a role with read only access to a component?

When assigning source control permissions to a process role, all of the options have to do with saving or delivering changes.  If I unselect all of these permissions, then users with the role get an error message when accessing the 'Integration_stream' claiming that they don't have read access to the 'Integration_stream'.  How do I give read, but not write, permissions to a role?

Users with this role should be able to download a component to their repository workspace sandbox area, and accept incoming changes, but not deliver any changes of their own.