yep, your right because all people who don't truly know about how fks work and or that bindings can be switched between skis don't need a binding that has a din of 18. He could need the binding because of weight or other factors you don't know what his ability is just by his post. Chances are he has seen that everybody loves this binding, which is good, but might want to do a little more research. Just because he asked an opinion question doesn't mean he isn't a candidate for an 18+ binding.
By the way I would not recommend, and nor do a lot of people, the continual switching of ski bindings. However, quiver killers do enable you to do this which is probably the only logical way to do it. Also an fks binding does not have a good interface for switching out different sized bindings. You have to take the whole assembly apart and ultimately everytime you do so you are making the binding more weak. Really any other binding would be a better choice if you were to be switching bindings through quiver killers