I do know that for fact. I have at least 3 personal friends who are mechanics, one in a dealership, and two who own private shops. They think I am nuts for waisting my time doing bleeding when I need to change a caliper.
Yep boiling would make the pedal go down. It also would make the fluid flow when you disconnect the pipe. Fluid running out the pipe would be a good thing. That way no air getting in. If then attached to a fully filled caliper not much air if any would get in. As long as the reservoir didn’t get too low.