I didn't see any mention, but will the OP have any checked luggage? If so, then isn't the luggage going to continue to LAX no matter what the OP does?

Has UA changed its one flight number mileage policy?
 

The through flight number for SFO-BKK via NRT used to give one segment and the nonstop mileage accrual (to my irritation - though it was little less than the actual via NRT).

Recently I went PDX-SFO-ORD on one flight number. To my amazement and pleasure I got miles for the two segments.

So I am at a loss on this issue.

Because even on a 'direct' flight UA now awards mileage based upon individual segments.

Easily. The gate reader scans the BP at each station and that adds pax to the manifest for the flight. If the BP isn't scanned in, OP won't be on the manifest and won't earn credit.

Bear in mind that this is a violation of the COC for the ticket and the t&c of MP (and other FF programs). If caught, the ticket will be refared and OP risks having his MP account closed. That's unlikely if only done once, but if he makes a fuss and that triggers a system audit to confirm that he boarded, it makes getting caught a certainty.

I've thought about this a lot of times, but I know I'll never have the knowledge (or courage) to do it. What stops someone from handing the gate agent the boarding pass, waiting a little bit and then just walking out? I'm sure you could come up with some kind of excuse, but I haven't put that much thought into it. I doubt they remember you even 5 seconds after they scan your pass.

I am sure there is something preventing that... I know I am not the first one who has wondered about that possibility and I am sure some people have tried it before.

1. People do offload for various reasons, but are manually off-loaded from the system.
2. The GA and FA do separate counts which must match before the cabin door is closed because the numbers affect weight / balance. I have been on flights where something has gone wrong (or maybe somebody snuck past the GA on the way out) and they have held the aircraft while they hand match BP to manifest.

Rest assured, if you aren't on the aircraft, you won't get credit.

This would be terrible from a security point of view. So, I definitely would not try this for fun.

Still curious what happened to the OP.