Extended warranties, when viewed from the other side of the fence, are a massive profit builder. Salesmen can make MORE on commission of selling an extended warranty than they can on the bike. ALL extended warranties on all products exist solely as a high margin up-sell.
Japanese bikes, in particular Kawasakis, are reliable. The odds are you will never use the extended warranty - and that is why they are so profitable for the sellers.
That said, it only takes one repair over a few hundred bucks to be glad you did.
In my life, I have sometimes bought extended warranties; usually not. I have never yet experienced it being worth it (used it if I had it) or wished I would have got it (could have used it if I had it).
I would say same goes for Kawis as what the service manager at the Lexus dealer told me about buying extended warranty for my car, when I asked his 'personal' opinion: "If you don't buy it, and you need a repair that would have been covered under it, you'll kick yourself for not getting it. However, these cars are so reliable that I've hardly ever seen any need for an extended warranty. Personally, I'd keep the money and take my chance as the odds are much more in favor of you NOT needing it".
What it boils down to is this. For an extended warranty, you are NOT buying insurance against unexpected repairs. You are actually buying peace of mind. If you are type of person who is going to worry about unexpected repair costs, and thus reduce the enjoyment of owning your bike, pay the few hundred bucks and buy the 'peace of mind'. But if two weeks from now you'll forget all about the extended warranty and never let it bother you, you don't need to buy it.
One exception: If you are the kind of person who just rides the hell out of your bike and doesn't take care of it well, you MIGHT want to get the extended warranty. But read the fine print about the conditions - you are almost certainly going to have to maintain it by the book and it won't cover any 'abusive' treatment.
Happy biking!