I had the same experience about a month ago on a Sunday afternoon at IAD headed to the IAD-SEA flight. It's a big knock on UA that they don't have a status line there -- and at LAS, btw. At SEA, LAX, SFO, ORD it generally goes a huge way toward minimizing the hassle factor -- and for people like me who value their time, it is one of the best parts of being a 1P (unlike 1Ks and UGS we don't always have the u/gs clear ;-)

Anyway, before resigning myself to the line at IAD, which stretched back all the way past LH and then back over itself, I noticed that the sign above security said "Access to all gates". It struck me that the other checkpoints probably gave access to all gates too, and sure enough that was true, and there was no line at the NW checkpoint just down the way.

Nevertheless, despite the fact that there's a trick, UA still gets big demerits at IAD for not having a better solution for status and F pax.