Ooh, this reminds me of my worst recent run-in with inexperienced travelers. Last month at LHR I was next in line for the scanner behind a family traveling with 4 or 5 large carry-ons -- rather than suitcases they were actually big shopping bags (think the reusable polyfiber kind), each bound up with a complicated array of knotted strings to keep things from falling out. The family obviously didn't speak much English and didn't understand the signs about liquids, because the following conversation ensued:

Screener (points at first bag): Are there any liquids in here?
Woman: Sorry, what?
Screener: Any liquids in this bag?
Woman: (thinks)... Yes.

The woman's husband proceeds to undo the mess of knots holding the bag together and unpack the entire thing, eventually hauling out a couple bottles of perfume... then some hot sauce... then a water bottle... then a couple cans of soda... and so on until the bag's contents (which evidently were largely bottles of liquids) were strewn all over the belt.

And then the screener points to the second bag. "Any liquids in here?"

"Yes."

Process repeats itself for the second, and third, and fourth bags. It took them over 20 minutes to get through. I didn't stick around to see how long it took them to re-pack everything on the other side though