Different communities and MAJCOMs have different rules/interpretations.
If we show to the jet, AMCC, squadron, etc. then my crew has started the FDP. Brief time doesn’t start our clock in AMC; show time (at the aforementioned locations) does.
If I’m awake and check the weather or SMS from my hotel room, then I’m not breaking crew rest by 202V3 2.1.2. If I get on the bus, I am still in the 12 hours of crew rest set aside for transportation, meals, etc.
This is why we have MAJCOM and Wing supplements...MAJCOMs have operational authority.