It's not so much about what they landed with, and more about what they
predicted they would land with:
The pilot in command must declare a situation of emergency fuel when the calculated usable fuel predicted to be available upon landing at the nearest aerodrome where a safe landing can be made is less than the fixed fuel reserve for the flight. The pilot in command must declare an emergency fuel state by broadcasting MAYDAY, MAYDAY, MAYDAY FUEL.
Note The emergency fuel declaration is a distress message.
You continue to crack me up, 43":
I heard some operators refused to move to the new rules.
I think you'll find that operators don't get a choice. The clue is in the word "rules".