(2) assuming the lounges are even open, an extra pax or two in a nearly EMPTY lounge won't "rock the boat".

Not for much longer... on their front page:
https://thecenturionlounge.com/
"As the health and safety of our Card Members and colleagues is our top priority, in light of the spread of COVID-19 we are temporarily closing all The Centurion® Lounge locations, starting on Saturday, March 21, 2020. American Express will provide notice here and on the Amex Mobile App when locations reopen."