I think even with all my electronics I can't remember the last time I got swabbed. I did once confuse an x-ray reader when I had two of the same model laptop stacked in my backpack (I had pre), and apparently really well aligned. He asked if I had two identical laptops and I told him yes, and offered to take them out. He just ran it through the x-ray a second time and paused and flipped through his image options then sent me on my way.