Originally Posted by
cfischer
not even the rate desk can sell you this illegal routing ...
In context the quote is
Notice that all of these paths look reasonable: they don’t leave the United
States and southern Canada, all are length 3 or less, and all arrive the same day. An impecunious traveler might be
willing to consider any of them.
The point is that you don't
know that's an illegal routing. For example, UA is perfectly happy to sell me SFO-YVR-YYZ-BOS (with a fare break in YVR). This is an absurdly long routing and happens to be expensive, but until you actually start pulling more data than a directed graph of flights you won't know that.
And the "impecunious" (which means poor) traveler, or the mileage runner, might be willing to consider such a crazy itinerary if it were in fact inexpensive.
As a more realistic example, I have seen SFO-SNA-SFO-MSP be less expensive than SFO-MSP (same last sector). That was even fancy enough that I don't think ITA found it.