overnight in JFK(?)
 

I seem to remember seeing this question (somewhere on FT).
I just received an email from Priority Pass, that their new "Wingtips" lounge, located in T4 (the only terminal in JFK, open 24 hours) is (also) open 24 hours.
The only "catch" it is airside (after security). How does one clear this obstacle, if they were flying out of another terminal and only intended to "camp out" in the WT, until your flight next morning?

overnight in JFK(?)
 

Buy a fully refundable ticket for a T4 airline, then cancel it once in the lounge.

I have a vague recollection that some of the PP lounges have a max 4 hour stay, you might want to double check if that's the case for the Wingtip.