Double Eagles, maybe...you are correct in your assessment (even though the last time I golfed I only hit two good balls all day...and THAT was when I stepped on a rake in the sand trap!)
I think I would have known if someone I caddied for got a double eagle. I probably would have gotten a big tip.
Par = 0, Birdie = -1, Eagle = -2 Double Eagle = -3.
Had to think it out.