Now because you actually won, which is a pretty rare feat, the caddie throws the originally agreed upon amount out the window and now wants more?
How does that sit with you when you hire a contractor? "Oh Oryguncoug, you just won the lottery? That $10k project is now $50k. I'll invoice you next week".
I understand the total $$$ isn't that big of a deal and Kuchar should have probably just paid it, but that is bogus. My guess is the caddie didn't do it a humble way either but felt entitled (straight opinion here).