For those who didn't know, the previous standard that still applies to pilots is that paid time runs from parking brake release to parking brake set. In fact, the aircraft parking brake is usually connected to a time clock computer system.

A typical domestic duty day might run for 14 hours, but only include 4 to 6 hours of paid flying. The rest of that time is preflight and post flight duty, including safety checks, managing catering, flight planning (for pilots), and a whole lot of waiting around in airports for the next connection.

If the boarding time pay is really only the boarding period, that's just a small part of it.