The AONE3 e-ticket itself says only 2x23 which is the same whether Y/J/F (which I find strange for what’s arguably each airline’s most premium sale). This I checked up-thread in February before buying, so I was somewhat prepared for the worst possible.

My experience so far seems that additional allowance reverts to if each carrier offers more for their class of service booked. Obviously I had no troubles with JL checking in at their First Class living room in Haneda where I probably could have given them anything and they wheeled it away to be checked in. Up to the chair I was sitting in LOL.

Interesting side note there… I had only two pieces (but a lot of hand bags - not a problem for JL F) since I knew I was connecting to AS, but they were packed to the gills at probably around 30k each, and the baggage receipts they brought back to me in the lounge together with my AS connecting pass were for 2x23, so maybe they did that since their system might have asked for an ADC just because of the AS flight, but it would have been rather impossible for AS to do an ADC for baggage on a direct connection in SFO between HND and RDM… pure speculation

it was the RDM-SFO segment where I had the near problem. And when I checked in the first time for the 25th, no one batted an eye but there was also an IRROPS situation. It was when I went back on the 26th that I had the stricter interpretation and then only waived because “the agent the day before made a mistake.” YMMV

AA Flagship First also has clearly published allowances (3x32) for transcon F (less for short haul J, which was why I called to check and they told me, vaguely to my surprise, that the PHL-JAX and JAX-MIA would have the same as the transcon). So they were applying the allowance of the most significant leg to the whole part of their itinerary… which is not uncommon but I suppose AA policy and not explorer policy.

Obviously BA allowed MIA-LHR with 3x32 so although I didn’t have much more weight I did use the 3 instead of two in order to pack more easily.

I’ve yet to do the LHR-NCE segment (that’s the one I need to reschedule as a no-show next but my times keep shifting). It used to be that BA kept the same allowance as the most generous among all their flights on the PNR (which would be MIA-LHR in F) but I think I read a change to this. Once I get booked into the flight I want to NCE I will check by phone like I did with AA, and either pay the fee or leave a bag to re-collect in London from my hotel here… A lot of what I have is winter clothing from my departure to Japan in December before the RTW, and I sure don’t need it in May, so if it’s free to take it to my home in NCE I’ll do so, otherwise I’ll leave it with my hotel here as I’ve done before and make a lightweight trip later.

Back to your point, however, AS has been the outlier thus far in my trip, but I only have JL, AA and BA to balance them against. Strictly strictly speaking, the ticket says 2x23, but almost every other carrier considers 3x32 the normal for F. I think in retrospect that’s why I have AS marked as my AmEx $200 airline incidental reimbursement. No other airline in memory has charged me for anything on the tickets I buy, and AS is indeed an outlier but at least one I don’t fly much. Their onboard team is quite nice, but their rules and enforcement is more of a discount carrier.

Final final afterthought… wondering if it would have made a difference if the AS flights had been booked under AA or JL codes… probably not but it wouldn’t make anything worse.