jsloan

They've started to add this to some of their fare templates, not because they're trying to discourage mileage runs, per se, but because they're trying to enforce price discipline in other markets. The intent is to disallow people from using an LAX-SIN fare for a cheap trip to Tokyo. (LAX-NRT / NRT-SIN-LAX, priced using a RT LAX-SIN fare with a stopover).

I'm not going to pretend that this is a customer-friendly change -- it's not -- but it's a heck of a lot better than some of the alternatives they could have considered, including eliminating stopovers or forcing HIP checks* at stopovers even on routed fares.

There's a YVR-TPE P fare that's about to expire -- it's been the subject of a lengthy thread on the premium deals forum -- that has this restriction too, so it's not just the cheap fares and not just SIN.

*HIP Check: Higher Intermediate Point (fare) check. When a HIP check is in effect, the fare must be calculated from origin to destination, from origin to stopover, and from stopover to destination, and the highest of the three is used. There's also a Circle Trip Minimum Fare Check, which is the same concept applied to a circle trip (A-B-C-A construction, where A-B, B-C, and C-A are each separate fares). UA waives this check on most of its fares, which is definitely customer friendly since the checks themselves are not.