Well, about 5 minutes ago at MK, a CM blocked us from waiting in the regular line and insisted on walking us around. Now it was pouring rain and lightning, so I don't know if that made a difference, but it was interesting, he wouldn't let us wait in line and this was at Magic Kingdom. The bottom line is we just follow directions, if a CM gives directions that are different than what is posted, we follow the CMs direction, as there may be circumstances we are unaware of and they are there to keep everyone safe. If no CM directions are given, we go with what is posted.
But at the end of the day, we just go with the flow, we are all on vacation and you just do as instructed, if not instructed, be nice to others and they will generally be nice to you. At Disney Springs earlier, a person told us he was grateful we were being loaded, as he saw us and he knew he had enough time to catch the bus. So
ECVs being loaded first can work to others advantage as well. All we can all do is our best.