I'm surprised you can leave 20 minutes early, even with all paying pax onboard.
at SWA it is only 5 minutes early with all expected customers onboard and I hope that most flight deck crews are cruising the top of the jetway to make sure that we aren't leaving any j/s we could be taking. sometimes agents get their priorities wrong (and put efficiently on time before customer service).
I don't know if the thread starter was commuting or not but I'm surprised how many people jumped on him. closing the door 20 early seems more like a legacy thing than an LCC trying to keep good customer service thing. then again, I'm just a pilot and I just fly the plane.
then again with 20-30 minute scheduled turns, it'd be almost super-human to leave 20 early; so we don't run into this problem much, FOM 5 minute limitation or not.
Man...those of you who don't think you would or could push 20 early if all ticketed pax were on board have NEVER operated out of JFK where this "incident" may have happened. During late afternoon push/ international departure bank at JFK, if I can get out early with all pax and get to the head of the line so I'm not #43 for take-off, you know I'm going to do it and dispatch will be more and happy to let us go...that's a heck of a lot less fuel burned on the taxiway and a plane load of happy pax when we arrive at their destination earlier!
cheers!