That advice from CX is simply wrong, and their ticketing desk would refuse to issue a ticket like that. A segment is a single flight number without interruption of journey. I suspect they are making the same mistake as other CX offices have with me (specifically Paris) which is to misinterpret "segment" as "stopover", not realising that if that were the case some of us would fly continuously with no stopovers for several days in order to get a huge number of miles.