I'm in London this week, and Minneapolis the next. The itinerary is SAN-LAX-LHR (one week elapsed) LHR-ORD-MSP (one week elapsed) MSP-ORD-SAN. Due to some arcane AA rules, the MSP-ORD-SAN can't be booked as part of the SAN-LAX-LHR-ORD-MSP trip (my travel agent said going from MSP to ORD would count as "going backwards" and you can't do that, even though it would only be to change planes).

As a result, I think I'm technically booked on a round-trip SAN-LHR-MSP, and a one way MSP-SAN. I think both are on the same PNR. However, likely because of the presence of the one-way, I had the dreaded "SSSS" show up on my boarding pass in SAN.

They seemed to be training new TSA staff in the SAN commuter terminal, so the secondary screening took a long time and involved three people. Everything was done multiple times.

Am I going to have to undergo this when I check in at LHR for the flight to ORD? I assume I will have to when I transfer at ORD to go to MSP. I have a two hour connection. Will that be enough time to clear customs, immigration, and the secondary screening and still be able to pop in to the Flagship Lounge?

I also assume I'll have to check in early in MSP for my return, to allow time for the asinine secondary screening?

Doing a full secondary screening just because an itinerary includes a one-way seems to pointless! It wastes everyone's time, increases TSA costs, diverts attention from real threats, and, since it is widely known, would seem to have no actual value in deterring any actual bad guys.