The way this event is set up they almost have to be this rare. Look at the rewards you get out of the gold eggs, rare flowers available only from gardening used in 3 star crafting, 10k allagan coins... deviled eggs... okay maybe not the deviled eggs...

If people were able to farm the crap out of the eggs and open as many gold ones as they want the market would flood with the flowers and one of the higher tiers of gardening would be put to waste until all of the flowers in circulation dried up after the event.