"Skiplagging" international ticket
 

Posting this here because it's in connection with a possible UA trip but it's more an airport question.

I might book my girlfriend and her mother on a routing of ATH-IST-LAX-(LAS) on a UA award. The arrival in LAX is late in the evening and the departure is the next morning.

If we decide that I will drive to LAX to pick them up, can they retrieve their bags in LAX? I'm guessing they probably have to clear customs in LAX and then re-check for the LAX-LAS leg, so it's probably a yes.

If we knew for sure what we want to do we would probably book it that way, and it's unlikely it would cost more miles, but we're not sure yet.

Yes, they will get their bags before they clear customs. The main issue with dropping last segment is in case of irrops. They would be routed to LAS via some other hub.

With an overnight in LAX this is IMO pretty safe. A delay won't cause an issue and they can certainly make an argument they were going to visit friends for the night and want to still be routed via LAX in case of a cancellation. Of course the risk in non-zero, but I'd say it is on the very low end for this one

It is not a violation of the rules to change your plans enroute. The violation is intentionally booking an itinerary that you don't intend to fly in order to get a cheaper fare. What you describe sounds more like the former than the latter as they are actually going to LAS.

If this is the outbound trip on a round-trip itinerary, you'll need to talk to the airline so that the return trip is not cancelled.

Whether intentional or not, the odds of having a problem here are essentially nil.
Yup. Another reason why it's pretty much always better to book award trips as one-ways.

In addition to Kacee comments above-
They must retrieve their luggage on arrival LAX to clear US Customs.
IF they were going to LAS they could drop their bags at the connections (exit right) or they could just take and drop at the connecting airline.
Therefore they should just exit to the left and join the zoo of people leaving.