Mmmm, I think it's a bit more complicated than that, since PEG (and indeed MEG) is a polymer present in all sorts of stuff - cosmetics, toothpaste, skin powder in compacts, foodstuffs, dry and wet paint, hair gel, deodorants. I suspect it just came up as a general organic material, and the shape of the container gave the scanner cause for concern. Same would happen with a jar of coffee.