Strictly speaking, you don't need to set the value to false here, since it still will be false. But I'd add a comment, like:

> It is possible that a client (e.g., the TCK tests) create ACLs (which we implement as nodes) and later removes the ACLs all without saving the session. If 'session.refresh(false)' is called, then this ACL nodes will not be able to be found, so we should catch the NodeNotFoundException, simply eat it, and continue.