I think whatever the actual policy might be, the main point is that GAs must have some discretion because of the different experiences people have had. I personally have been pulled up to the front after boarding as well as been UG'd with a ton of higher elites on the flight because I was an FO running late and boarded last.

It appears to be the same scenario with AMEX companions, some will do it and some don't. My personal feeling is that Medallions shouldn't be flying in the back with open seats up front, so I'm glad when I hear stories like this.