WOW! Very good read and definitely learned something (session based clicks).
I think if you watch the ads that appear on your own screen, you will notice this eventually. For instance, during a "session" last fall, I was searching for Adobe Creative Suite 5. And pretty heavily.
Even today, several months later, google is serving up ads for Adobe Creative Suite 5. This must be what these advertisers are complaining about...if I search for anything (tesla, electric cars, etc) I am still seeing ads (skyscraper and 250 x 250 boxes) for the Adobe Products. This would be a classic issue of these session based ads...something I searched for in the past is still being presented in ads. Obviously, google is not really putting a time limit on when I searched for a product during that "session".
Always happy to read about trends or topics, even if it does have a negative connotation.
And always happy to be able to reg a couple of names in the news (sessionbasedclicks dot com and sessionbasedads dot com). That's why reading is FUN(an)Damental.
Fun and Mental