Originally Posted by Keter

I have made some brief search for treatment of mistakes in Spanish contractual law (which shall be applicable for IB tickets).

And what i found is actually saying that IB will lose every single court case unless stupidly managed.

So, Art 1265 of Spanish Civil Code is what has general guidance for mistakes. Nothing surpising here. However, the book refers to the ruling of the Supreme court on 21 June 1978 which says the contract can only be voided if the mistake is excusable. And my strong belief is that IB will never prove to the court that not monitoring the applicable prices for one week (especially those of high risk - business and first fares; it was posted on FT after one week the fares were published) is excusable. There can be a claim that it is IATA fare not IB but it is a routine part of their business and if they have no controls here it is under no circumstances excusable. That's just a simple business risk.

I could be wrong in my understanding so any constructive challenge is welcome.

You can get a summary of treatment of mistakes in different law in the following book accessible in Google: 'Contract Law and Practice: The English System With Scottish, Commonwealth ...' by Michael H. Whincup. See pages 304 or around.