I wanted to add a few comments here. For models under 10 lbs, I do not believe shunting is necessary. This doesn't mean it cannot be applied to provide an additional layer of safety, which is why they are used. What it does mean is that these models are smaller in size making it more difficult to incorporate a shunt system. In addition, they do not pose as much of a safety hazard as the larger models due to thier lower mass.
That is where shunting comes in to play and should be used...to help prevent accidental discharge of ejection loads, staging, etc...on larger and heavier models. A true shunt would both remove the connection from the source and short the leads to the load, such as a match or igniter.
This is where a double pole rotary switch would work the best as it could perform both tasks at once. The screw switches are IMHO the most reliable, followed by high detent, high quality rotary switches. If wired correctly, Phone Jacks make a good shunting device for shorting leads and have been used on many models with great success. Note I said used correctly because all switches have their limitations. That is why the die hards still just twist wires together for shunts and powering/arming their electronics.
That is the beauty of our hobby, there are so many ways to accomplish the same end result and although some may be a bit more reliable than others, they all produce the same end result.