Airlines go after chronic offenders -- people who have dozens or even hundreds of round-trip flights and always throw away the return coupon, for example. I have never heard of any airline going after a first offender. If you fly often enough, eventually you wind up breaking some fare rule, no matter how much you might try not to ... the rules are so convoluted that even agents don't know most of them. Obviously the RTW ticket does require flying RTW, and not ending in your home country breaks this rule (hence Viajero's excellent suggestion, technically that puts you 100% into compliance with the xONEx rules). Even without flying the last sector, in practice CX won't come after you (it is only the issuing airline that counts, CX in your example -- AA is not involved in any way with your ticket). You have to make your own decision about this, but I'd say it is low risk no matter what you do.