Because your itineraries violate their contract of carriage. You are circumventing minimum stay requirements in order to get a cheaper fare.
<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by scook013:
Can someone explain to me this issue with the RPU? Why is it that they can stop me from putting together an itinerary that will save me money in the end, when I'm going to be paying them what they charged me?
i.e. this could be typical for me:
Ticket #1
X-Y 1/7 (Mon)
Y-X 1/18 (Fri)
Ticket #2
Y-X 1/11 (Fri)
X-Y 1/14 (Mon)</font>