Go ahead and affix your bayonet to your Glock. If you ever use the gun in a defensive situation, the first thing we well see on the news is a closeup picture of your "evil killing weapon". Come on, let's get back to reality here. The media will drag you through the coals like you were a modern day axe murderer. The prosecution will say your were a vicious killer waiting for your first victim. When everything is said and done you will be wishing you could find a hole to climb into and hide the rest of your life. Let's get past the testosterone rush here and use our heads and some common sense.
Should you be able to place a bayonet on your gun? Yes you should be able to. Will you place your bayonet on your gun and use it in defending your life? Sure, if you enjoy the thought of spending the rest of your life miserable and broke from legal fees. So, go ahead, be that super stud! Hey, at least your gun will look real cool!