To add a bit of levity here, if TSA screeners still do their jobs as well as they've done for the last two years, then sure, why NOT try to sneak a plastic gun on board?  In a well-publicized real world test, TSA screeners failed to detect over 90% of simulated guns, knives, bombs and explosive devices.  This was not at all a "sneaky" test amounting to a "trick question."  The faux guns and knives looked like common guns and knives.  The faux bombs and explosive devices looked for the most part like bundled sticks of dynamite with a fuse hanging out or round bombs that look like the U.S. Army Ordnance Corps insignia - items that anyone who watched Rocky and Bullwinkle or Wile E. Coyote and the Roadrunner cartoons as a kid will surely remember and recognize immediately.