Thanks very much for your feedback.

The explanation that a 6 day minimum will discourage mileage runs is certainly plausible. Yet there are two issues that challenge this rationale.

The first issue was brought up by martin33 who noted that H fares also carry a 6 day minimum. One can presume that a passenger will not pay an H fare simply to execute a mileage run.

The second issue is that there are a small number of Asian destinations (NRT, NGO, SEL, KIX) which are closer via a great circle route from the west coast of the US than are LHR, CDG, or FRA. Yet Japanese and Korean destinations carry the same 6 day minimum requirement.

One is left to ask, "If UA wishes to discourage mileage runs, why not place 6 day minimums only for TPE, HKG, BKK and SIN and only on Q, V or W booking classes?"

Thanks.