I am going to address this blog entry to my fellow Flight Simulation Addon product developers. Some are more experienced than others, we all have a common goal, though: To produce quality addons which will make our simulation audience happy.
Fellow developers, PLEASE don't alter other people's (or companies') registry entries or paths. I know you think you're doing the world a service, but in fact, you're causing (inadvertently, I know it) severe support pains and aren't even aware of it.
Altering a registry key value, ESPECIALLY one that is meant to be controlled BY THE USER, goes against all programming principles we've all learned while programming under Windows. And when that registry key happens to be the setup path where Flight Simulator is installed, you're adding pain and suffering above and beyond your intended goal.
So... please... for the sake of sanity (because where I've been, I am sure you will one time have to be as well). Don't do it. (or, at the very least, alert the user that you will be doing it... or... don't do it. Don't. Don't. Hope I was clear).