Hardly.

By "snatch and swab", I was referring to the practice of an agent going to the cutout in the x-ray return and picking up a laptop to be swabbed at the ETD machine.

If the laptop is already out of the bag, it makes it easier to select a laptop, rather than making the ETD person either look at the x-ray or open a bag to determine if it contains a laptop.

By observation, it appears that laptops are the most common thing being swabbed.