Checkpoints and Borders Policy Debate - LAX (united terminal) - SFO (connecting flight) - NRT (is opt out possible?)

I know someone going to Japan. They were wondering if:

1. LAX United Terminal - backscatter or millimeter?

2. SFO connection to Japan - also United flight - do you need to go through security again to get on your flight to Japan.

3. Japan - do they allow opt outs here (curious about return trip)

4. on the return trip, do you go through customs in SFO or LAX? Do they make you go through security to leave the airport?

I believe you can only "opt out" in Japan for medical reasons. I say "opt out" because they use WTMD's only. Not sure why anyone would want to get patted down in lieu of a metal detector.

I know someone going to Japan. They were wondering if:

1. LAX United Terminal - backscatter or millimeter?

2. SFO connection to Japan - also United flight - do you need to go through security again to get on your flight to Japan.

3. Japan - do they allow opt outs here (curious about return trip)

4. on the return trip, do you go through customs in SFO or LAX? Do they make you go through security to leave the airport?
IIRC, LAX is all Backscatter - but I avoid LAX like the plague, so someone please correct me if I'm wrong.

UA's operations at SFO are all connected airside, so you will not need to re-clear security if connecting from LAX - HOWEVER - some flights are now arriving at Terminal 1 (rather than T3 or International G), and require a shuttle bus ride to get back to T3/G. They've changed the minimum connection time to 45 minutes, so check your itinerary and call UA if your connection has become illegal.

Coming back into the US, you clear Customs & Immigration on first landing, so if you're connecting at SFO to return to LAX, you'll clear C/I at SFO. You WILL have to re-clear security at SFO upon arrival from an international flight.

[QUOTE=Critic;18802452
Coming back into the US, you clear Customs & Immigration on first landing, so if you're connecting at SFO to return to LAX, you'll clear C/I at SFO. You WILL have to re-clear security at SFO upon arrival from an international flight.[/QUOTE]

To clarify, on the return trip, when you land at SFO, you will have to go through Immigration, get your checked bags, and go through Customs. After that, you've effectively arrived at the airport for a domestic flight. You need to go through TSA, so you'll have to recheck your bags and don't forget any Duty Free liquids or anything that won't fit in your Freedom Baggie. If you have just a carry-on but bought wine or perfume or something at Duty Free, then you will need to stash it in your carry-on and then check it for the flight to LAX.