Dan (of Dansdeals) has pointed out that you can still save money on some sectors by buying both seats and using them both, with one as an EXTRASEAT.

It's an interesting use of the category 13 accompanied travel fare restrictions. I'm so accustomed to seeing this for promotional business-class itins (where price discrimination against solo travelers makes a lot of sense) and it's so interesting to see this show up for short domestic trips.

There are a couple of frustrating issues as a plain old person who is booking trips for the family:

- Now if I am booking a trip for me and the spouse and the 2 kids and I want the lowest price, I need to search for prices for 1 pax, 2 pax, 3 pax, and 4 pax and compare all 4 results.
- This was already true -- suppose a flight's fare buckets are, say, W9 S3 T2 L1 K0, I may be best off booking 1 passenger on the L fare and booking a 3-pax itin into S (if S stays open after booking L, possibly using United's dynamic price smearing at the lowest bucket).
- But now in addition to booking 1+3 pax I need to check whether it's cheaper to book 2+2 pax or 4+0 because in addition to looking at fare class inventory, I have to look at whether there's a category-13 accompanied travel restriction on the cheapest T/L fares that I can only get with 2+ pax.

All this is IN ADDITION TO, and completely separate from, needing to price out every domestic family trip as a round trip vs. two one-ways, because there may be round trip fare discounts, but also there may be cheaper one-way fares that are not combinable.

Quite a lot.