If you are just throwing away the last segment, then none of the rules would worry you (until they try to hunt you down). Although, for the records, TPE to NA does not allow stopovers for class I/D tickets, although tickets to SE Asia still allows an inbound stopover at a cost of 1,500 TWD, but not for outbound. To make things confusing, however, TPE to destinations such as Australia allows 1 free stopover outbound, but not the inbound.