It would also be interesting to know about actual experiences in purchasing tickets on other long haul intra-continental flights that violate the constraints imposed within the regular ticket. That is, in addition to your question about the second "transcontinental" intra-Europe trip, what about a second trans-North American segment or trans-Australian segment (within the 20 segment limit, of course).? Are these still ambiguous or are they definitely prohibited and it is only the Europe one that is indefinite?