> In the case that we are unable to find a reasonable alternative flight(s) or other means of transportation, due to a disproportionate price difference between the potential alternative transportation and the original price for the unused flights, we may agree with you on our proportional contribution to the costs associated with a mutually agreed upon alternative transportation.
This doesn't sound like a 100% guarantee. Most of the times on the day tickets will be a lot more expensive than advance purchases.
Alright, this following comment is not an official communication by Kiwi.com, it reflects solely my personal guesses/opinions.
I'm not sure about the details since I don't have much to do with the legal side of things, but I would assume that Kiwi.com had to put this clause in to avoid having to pay when a flight's price is 1000x higher than it should be as an error fare, or similar cases. I've personally never heard of a case where expenses weren't fully covered because of this clause.
This doesn't sound like a 100% guarantee. Most of the times on the day tickets will be a lot more expensive than advance purchases.