Oh forgive me, I read

"be traveling in an F or J cabin (whether via upgrade or purchase) on the international segment (to/from Europe, Asia, Central and South America, and Mexico City, excluding the Caribbean and other destinations in Mexico) of their itinerary"

to mean you must be about to embark on your international segment in F to be allowed access to the lounge.

Phew!

One other off topic question: does F on the MD80s suck? Looks like my equip is MD80 ORD-SFO....