The bolding is mine. Thanks for your explanation. Bolded, because I wouldn't even think about options like that, There just is not a mean, let alone violent thought in my repertoire. And it still is hard for me to understand, but of course you are right.

I know that this is not an option but for argument's sake and in an ideal world :YES. Here is why, I am a peaceful great-grandfather, whose only wish is to live a very long life alongside Mrs. EX. It's funny but it's the truth, instead of smashing flies, we try catching them and release them out the door alive ( so maybe we are a little nutty ), I am polite, I am friendly, I am retired and therefor don't wear business attire. Why do Mrs. EX and I continuously attract the extra attention at U.S. security, why so many other seniors? This begs for common sense!

Same is true at NRT, and has been for over 20 years, long before 9/11. You can't touch your checke bags, but still have to go through security immediately on arrival.

I always thought it was because the Japanese did not want to have to trust anyone else, and wanted to be sure anyone getting on to a plane in their country (even if they never officially entered the country) would not be able to have anything illegal.

YYZ (and maybe YVR?) have a way for passengers to transit without security and customs on checked bags (but with immigration) as I recall.

Everyone is abused by the TSA; you are not alone. Hopefully that is of some minimal solace next time you suffer indignity at the hands of the TSA/CBP.

ARI wrote "YYZ (and maybe YVR?) have a way for passengers to transit without security and customs on checked bags (but with immigration) as I recall."

We came in thru YYZ last week from HKG on AC and connectd to LAX on AC as well. There was no way to avoid Canadian security and their full body scanner and/or equivalent as I mentioned before.

Mrs. EX and I thank you for your kind thoughts.

If you deal with TSA long enough, that may change.
Common sense is not part of the TSA performance.

Seriously, though, you are probably attracting the extra attention simply BECAUSE you are polite, friendly, etc. They need to fill a quota of extra harassment screening for a certain number of people. Obviously, it's more pleasant for them to harass search people who are quiet, cooperative and uncomplaining rather than someone who is likely to ask a lot of questions, be difficult, ask for their supervisor, etc. So when they "randomly" select people for extra scrutiny, polite retired people on vacation are an ideal target. (Read this article about a retired female police chief who was also singled out.)

Or maybe anyone who can still be polite and friendly after being harassed searched by TSA is obviously suspicious!

Try this next time - arrange with the lovely Mrs Ex to start an argument while you're in line for the checkpoint. Something trivial and unrelated to aviation safety. Escalate just as you reach the first TSA person. I'll bet they leave you alone!

That's only true if you're connecting FROM an international flight TO an international flight, and that's because (unlike airports in the US), YYZ has a sterile transit area. If you were connecting through YYZ to a US flight, you'd have to pick up your check bag, clear US CBP, and then CATSA security to get into the transborder departure area (which is separate from international departures).

I apologize-- I meant for flights from the USA, not to the USA.

Yes, this exactly correct. The USA has this ridiculous policy of making you claim your luggage and go through customs with it, so you could in fact have a knife in your luggage, so re-screening makes sense (but not of course if the Americans did like EVERYONE else does and let you check your baggage through to your destination).

But what about everywhere else? If I fly, for example, from Cairo to Copenhagen, and I change planes at FRA, I do NOT get anywhere near my checked baggage, but I still need to go through security at FRA.

Of course this is in part because on arrival from Cairo, I am mixed in with unscreened passengers, but why do they do that? Why not just put me right into the sterile side of the airport? I have already been screened, and of course, IF I was a terrorist and the first screening failed, I would have carried out my mission on the first flight, not waited to see if I could carry my explosives back off flight 1 and onto flight 2.