Approval of timecards with Change requests pending

Summary:

Recently we set up the Time Change Requests functionality, and its all fine, with the exception of one area.

An employee submits a change request this then goes to the manager, who can approve or reject the change request.

However in a scenario where the manager doesn't or forgets to approve the change request and goes in and just approves the timecard. My expectation was that out of the box the timecard would not submit without the change request being approved.

In our set up that doesn't seem to happen, what have other people done here? As I say I would have thought it would be standard to deal with (approve/reject) the change requests then approve the timecard.