Has anyone done a correlation between <5 seats left and EF, seatcounter or "classavailability"?
Not yet; I can't see the thing anymore ..

(although a Mouse over pops up some text still ...)
[EDIT]
OK I checked it out and it seems reasonably accurate.
One thing I saw though is if the class description
price being shown has 5 or less seats, the 'warning' shows.
e.g. a red e-deal MEL-ADL tomorrow is showing $85 and has the warning, hoever, this flight is actually " J9 D9 I0 B9 H9 K9 M9 L9 V9 S9 N9 Q9 O9 X9 E2".
The $85 price is E class so this is correct.
Investigations