Your knowledge of UA's procedures is incorrect due to the fact that it isn't published to the public by UA (by choice.) It is common for the publics assumptions about internal policies to be incorrect, much as my assumptions about Apple's internal policies are most likely wrong (I am a customer/stckholder of theirs, yet they don't send me their employee policy book.) DOn't sweta not knowing. You wern't supposed to. FT makes people THINK they know the ins and outs, but it is mostly about theories, unless supporting doccumentation is made public.

No need to board last...Seats are cleared after the cutoff time, unless their is a surplus, and they are cleared earlier then Deadheading pilots are "must ride" and will board the aircraft no matter when their reservation is booked, how full the flight is, or when they check in. While one may say that this is unfair to whoever happens to get the boot, if you ask the 100+ passengers on the plane the pilot is deadheading to fly when you cncl their flight due to lack of crew, they would be all for making sure a deadheader gets on his inbound flight.

As for the meal... To an infrequent elderly NRSA (i.e. a grandmother/mother of an employee) who had the FA take her meal order. Now she gets booted. This doesn't happen all the time, and no "manual" is given to people on what to do in regards to meals when downgraded. The woman was told by her grandson/daughter "If you get booted, just go with the flow and don't make a scene." They never told her what to do with her meal that the nice young FA in the galley is specially cooking for her. She dicides to ask "Excuse me maam...Will I still get the Charlie Trotter omlette served to me that you are cooking now?"

It's as plausable (more so if you ask me) as any "The GA and pilot were selevting the elderly as they are easy to scam based on the dateline NBC special about Irish Travelers in GA/FL that they had watched last month" theory.