Curious if anyone has any recent experience with this -- I've been reading various things online that range from "don't worry about it, just don't do it frequently" to "Lufthansa will reprice your ticket based on the part you actually flew, and send you a bill for the difference". It's hard to get any actual concrete examples one way or the other, though! There's also that one pending court case where LH sued someone for doing this; as I understand it, they lost, but on a technicality, and have filed an appeal.