Things are a changing out there. Science based FAR 117 is getting ready to raise it's ugly head again.
Buddy of mine is CO of the local ANG squadron and he has a lot to say about the current system. He gave an example from this last weekend. Junior International WB FO uses the Drill weekend card to get the weekend off. PBS awards him the weekend off as it should. It also awarded him a 3 day international trip that got him in at 0700 on friday morning. Pilot walks across the airport and picks up a 24 hour Alert Duty knowing that he can sleep off the fatigue he just experienced. Saturday morning he does his normal weekend duty which included a flying mission. Monday morning PBS gave him another 3 day International trip. This pilot was totally worthless to the Guard and the Company he works for and to the Civilians and Customers he is supposed to serve. The Guard units are starting to implement Fatigue Mitigation Programs that will stop this abuse and dangerous practice.
FAR 117 covers all commercial flying activities and duties. Flight Instructing, Charter Flying, Corporate Flying, Crop Dusting, Tours, and all other paid activities. The FAA is very seriously thinking about adding Military Flying and related duties as one of these activities. That will change everything.