Originally Posted by keithguy
Nested tickets in general are allowed. Nested tickets for the purposes of circumventing a minimum stay requirement is not allowed (back-to-back), but since none of these fares had minimum stay requirements, all is well.
The rule could be interpreted as "this traveller could be flying BUF-PHL-LAX directly, but is instead flying BUF-LGA-LEG-LGA-CLT-LAX on a nested ticket. The primary purpose of this trip is to earn miles. Therefore, the traveller is using additional connections to earn miles" if the airline so desires.