King Kong doesn't count
The clue asked which constitutional monarchy's citizens drove around with a car sticker of HKJ. Two of them guessed Hong Kong; the third guessed that, but changed it to Jamaica.
People. Have you ever heard of the king of Hong Kong? It's part of China, after all.
I'm not saying Hashemite Kingdom of Jordan should have leapt to your mind, but ... Hong Kong? Really?
(And yes I know, Final Jeopardy, they can't not answer - or at least not answering won't keep them from losing money, but still. I'd rather put a blank than an answer like Hong Kong is a constitutional monarchy)