Strategically, yes. Tactically and operationally, usually not, as planes need to be at certain places at certain times. That, and the cargo can make up a huge portion of the difference. Though if it's a small outstation with more then one flight a day, and both in/out are empty, and there's another turn-around that day, and all segments combined won't fill the plane (both pax and cargo)... then sure, nothing stopping them from canceling a flight that's under-booked.