My personal experience would strongly disagree with "usually" here. While I can't really be sure I've never seen one, none come to mind on my travels across US/

My personal experience would strongly disagree with "usually" here. While I can't really be sure I've never seen one, none come to mind on my travels across US/Canada/Mexico/East Asia (though I've really only been within Canada the last couple of years). I also go through the trusted traveler line, and the rules there are _usually_ different (but not always!) and I definitely don't recall seeing any sign specifically addressing the rules for that line at any point. Except maybe one at the start clarifying _who_ can use the line (though on that one I've also had the TSA agents go ahead and explain the rules entirely different than the sign they were standing in front of so...).