I don't think this is worse. That was done often in the days of the Saturday night stayover required for travel. The back to back would be purchased from the first city as the origin with a return in the distant future that you could indeed take or intend to take (a free round trip to wherever is a way to look at it). The second originated in your destination city (with a different airline) with a return that made the second possible. If your plans change so that you don't make the second round then you're out the money for the second trip which you might have wanted to take. I remember doing this once on US and booking it by phone, for both trips and being open about it. She even told me that it was called back-to-back ticketing and then issued the tickets. This kind of thing led to the one way fares we see on the web - but international flights still have these types of rules (one week stayovers and so on).