Since different groups accrue sick leave at different rates, we don't use Red Rover to track sick leave. When I have to adjust leave leave for any reason, I make a note of why in the note box that is visible by the admin & employee.

We have the system set up so if the employee is out of that particular leave (sick for example), then they cannot put the absence in. Our staff know if that is the case that they must contact the secretary at their building so that the absence is put in using unpaid leave reason. Staff are aware if that reason is put in for their absence, then they aren't getting paid for those days. Sounds like a communication step to send to your staff on the issue.

We use the notes box in the absence noting that all available sick leave has been exhausted, and will then change the absence reason to LWOP.