If a person and their property has been properly screened then what security benefit do these types of questions answer?

Out of HKG In the past, I have only been asked specifically asked 2 main questions. 1. Did you pack your bags yourself and have you left them unattended? 2. Has anyone given you anything to take back? Recently flew out of HKG bound for the USA and this time some additional questions. What other countries have you visited? How long was your stay? What is the nature of your work?

The agent saw my many stickers on the back of my passport and asked if I was a frequent traveler. Then said they needed to remove the old stickers.

The reaction when you tell them, I was only in the country for a day, a few hours, or I am going back on the same plane I just arrived in :D

Indeed. Once had a difficult time in Aberdeen, Scotland with their immigration official understanding why someone from so far away would be only in the country for a few hours...

Last week, I flew MAD-ZRH-SFO on LX and only had a 1 hour transit at Zurich. Plane was delayed out of MAD and laded at the A-Gates at ZRH. Made a mad dash to the E-Gates with 15 minutes to spare. Then, came up to a passport check desk for the airline. When I was cleared, started to walk to the Gate and off to the left was little booths with a sign above stating US Immigration. Some people were pulled to the side. As luck had it, so was I. The Agent, I believe LX, started to ask about my itinerary and what I was doing for the past week in Spain. He went further and asked about Hotels I stayed and the train station I left from in BCN. Finally, he asked what City in the US I lived in and asked me to state the Postal Number.

I had no problem with these questions and understand they have a job to do. I was more concerned about my flight and thankfully made it.

A month ago I flew from ZRH to JFK on AA. Except for pax on a special list (in the past randomly selected had SSSS on their bps) no questioning occurred.
On June 12 I flew on AA from LHR to JFK, an agent at the entrance to the boarding area had a list of 15 names, only those pax had extra security: checking c/o for explosives and extra "patting", no other security questions were asked.
I did see an agent with an ipad approach a single pax, seemed to be the first person in the boarding area she encountered was asking that pax only some "extra" security questions(?), she could have been doing a survey(?).

In MAD this week, the only security question at the entrance to the check-in counters was whether we have Global Entry. As we were boarding the plane, we were asked if anyone at the airport has given us anything to carry for them.

How does this work--is it if someone says that they have global entry, they quit asking questions but if not they continue to ask questions? I never thought that this was a benefit of global entry.

Was this for check-in on an American carrier (such as AA) or a European carrier (such as Iberian)?

Nothing was done to verify our Global Entry status; however, we answered the question confidently and without hesitation. My daughter offered to show her GE card, but the security interviewer said it was not necessary.

That was the only question asked.

It was at the entry to the American Airlines Priority check-in counter.

It was quite a difference from the manner in which we were treated by AA's security screeners in Madrid three years ago, when we were interrogated ad nauseum about our arrival date in Spain and our itinerary, and my daughter, a Global Entry member even then, was saddled with the SSSS mark of Cain.

Interesting. I think it was just about three years ago in MAD, Delta airlines, and I got the SSSS. It was an over-the-top experience. I was grilled about my travels, had to produce proof of my hotel stay, bag searched at the checkpoint and searched again at an xray across from the gate. Time-consuming.

Just got SSSS two weeks ago at AMS. KL to the USA.
Passport and BP scanned, shoes and belt off and swabbed, hand luggage exterior swabbed, Kindle swabbed. Five minutes. Was expecting much worse.
Amusing. Lady in front of me waiting for secondary said she thought the esses meant she'd gotten upgraded!

Once I had a tight connection due to a delay, and they had a special immigration lane for people with tight connections. I try to fly through whenever possible, they seem to be very efficient + polite.

AMS Super Screening