I would say if you have to ask don't show. It gives information away, and this is bad. The only reason to do it is to manipulate our image, but we have to know how our opponent will react to exploit this. The act of showing is a pretty clearly volitional act, so some oppoenents might note this fact, and gum up the works turning it into a leveling war. While newer to the game this is a marginal way to make gains at best, and may well often just make you shoot yourself in the foot by misapplication.