The above very controversial statement was made to me by an HKG GA and her supervisor.
I failed yet another upgrade which went on the DM and hence decided to credit the upcoming flight segment to another *A account and as I plan to fly UA much less the next year. The GA grumpily did as I demanded but her colleague intervened saying that I could not sit in E+ if I chose to credit the flight to another program.
I duly dug out the printout from the united.com website which indeed confirmed that restriction for the purchased Economy Plus Access but also clearly stated that 1Ks are entitled to fly E+.
The first GA then sang "you are not a 1K when you are not flying on United", to which I remarked that she might have missed what kind of plane she's playing the GA for at the very moment. This greatly offended her and she grabbed a sup. He then distilled her nonsensical statement into "you are only a 1K when you are flying under your MileagePlus number".
At this point I cannot help but acting as a major nuisance "so you are saying that I actually cannot call 1K reservations or use that Red Carpet over there because I am not flying at those very moments?". To which he had the temerity to answer "Technically yes. But unlike E+, these benefits were for '
1Ks on the ground' ".
The ugly truth is that the two might actually have a point - that UA really isn't providing their own elites E+ access when crediting their flights to another program. But they chose to word their conclusion in the worst possible manner

.
My first thought was that there is no point in arguing with idiots. Especially those who suffer from the impression that they are doing 'the right thing'. But then it occurred to me that this could be the key to all the troubles I experienced with UA more recently: there are two species of 1Ks: "1Ks on the ground" - the ones who always get the good seats and the upgrades as they are recognized as 1Ks even when not airborne and then those poor 1K-buggers like me who become 1K upon wheels-up and then get their first meal choice ... but are reliably skipped on the upgrade pecking order

!