i cut my teeth in audio working for RCI sound systems out of D.C. back in the day, the system install division of RCI used to manufacture the audio gear used by WHCA, which mostly consisted of shure 267s and various splitters and custom panels for feeds and such, so RCI was a preferred vendor in the D.C area. so yeah, i did a few POTUS gigs.
the deal with WHCA is redundancy. it's all about fail safe. we used to have a preset package of gear that went out on all POTUS gigs that consisted of all the multi-pair they wanted for various press feeds, etc. as well as press mults [WHCA may still use RCI press mults. they did for at least a decade or two], offstage announce mics [also a pair of redundant 57s], offstage powered monitors, etc.
aside from the fact that 57s sound like 57s, the gigs were usually pretty straightforward. i did a lot of clinton events and if it was late in the day he'd get hoarse, but would still be pretty loud.
i would usually run one mic in the pa eq'd for feedback, and the other straight to record and control them both with a single VCA, although i usually didn't tell WHCA that. they didn't like 'change'.
most of the other stuff has been mentioned. yes, the lectern is armor plated. yes, they would have extra armor plates beside the lectern in 'exposed situations'. and yes, it is cool to stand behind the 'goose' and do sound checks. although WHCA usually insisted on their guy doing it most of the time.
now if you want to digress, i can talk to you about the stuff i found doing gigs in the White House...
nah, never mind...
have a grade A day...
brian maddox
www.fcfchurch.com [yeah, i work at a church now...]