I mulled this over.

The cheapest way to accomplish this for Hexagon would be to change when CAESAR checks for available licenses, and how CAESAR reacts.

Presently, CAESAR just shuts down.

If CAESAR instead were to disable the ability to save, error check, or run, then CAESAR itself could be the free viewer.

Though I'll admit that I'm not certain what risks Hexagon opens itself up to by not shutting the program down.