Editorials Checkpoint: Churlish July 31, 1997 Share 1 -- Lugging a laptop computer through the security checkpoints of a few airports can be a learning experience. Here's what Insider learned: *At Washington National, you are asked to place the bag on the conveyor belt, and it goes through the X-ray machine unopened. *At LaGuardia, you do the same thing, but after the unopened bag goes through, you are asked to take out the computer and turn it on. *At Bradley International in Hartford, the process begins the same way, but you are asked not only to turn on the machine but also to place the empty bag back on the conveyor, so the bag can be scanned without the computer. It occurred to us that the security people, far from being randomly irksome, were getting more stringent as we moved north and east. Since this particular trip ended in Hartford, we were unable to continue our research in, say, Boston or Bangor. Perhaps readers could connect these and other dots on the security map.