Monitoring crew legalities is the primary role of the scheduling department. However, monitoring is not enough. Knowing that a crew member has gone illegal when it is too late to solve critical issues has an adverse affect on the carrier’s revenue and reputation, and often causing FAA disclosures and fines.
During the day-day, the Operations Department must make moment-by-moment decisions as flights and crews are affected by weather, sick calls, airport delays, mechanical delays, etc. Typically those decisions are made without being able to anticipate the outcome.
Typically Schedulers are tasked with a reactive role to crew changes, instead of being able to be proactive and plan ahead for a potential legality issues related to delays or cancellations.