Recent EU law cases against airlines, especially in Germany, Belgium, and Denmark, have all ruled against the airlines. While nested tickets and/or back-to-back tickets may well be within the Contract of Carriage by the airline, that does not mean that the contract is legal. And in fact, the cases which I refer to specifically have forced airlines to accept that a consumer may buy and use what they wish and the airline cannot make arbitrary rules because it suits them better financially. As a recent example, if a consumer wishes to buy a roundtrip ticket and not use the return because the roundtrip ticket costs less than a one-way, the airline legally cannot do anything about it. In the VERY consumer-friendly Italian courts, they are more than welcome to a legal battle with me if they wish. They'll lose.