I think this is so annoying disabling the shadows without consent of the simmer. I'd like to suggest that you make it optional.
I think you are confusing the automatic switching of airplane shadows depending on altitude that happens ONLY inside of the area of an FSDT scenery, with the suggestion to turn if off when using LEGACY AI models that has been discussed here.
The Addon Manager DOES NOT disable shadows "without consent", it controls AI shadows to be on/off depending on the altitude, and ONLY when you are flying inside an area of an FSDT scenery, but your original setting in the FSX.CFG is preserved and restored once you exit from the area.
This switch is NOT made in order to fix compatibility with legacy AI models, it's made because, with our latest sceneries ( those with full DX10 compatibility and 100% native FSX code ), the ground textures are NOT compatible with airplane shadows.
Over a certain altitude, you WON'T SEE THE SHADOW ANYWAY so, it's totally useless to keep it on, losing performances, because FSX is still trying to draw the shadow, but you won't be able to see it due to how the ground scenery has been made in order to be fully DX10 compatible and fully FSX native, with all the performance benefit that comes with it, like the memory saving you can achieve with DX10 and the net 30% fps increase that a scenery for, let's say, JFK, gained when switching to native FSX code.
If we made the airplane shadows "optional", as you are suggesting here, you would likely see a performance decrease with NO visual benefits whatsoever, because even if you had the airplane shadows enabled, they won't be visible, but they would still cause an fps loss, which would be higher the more AI you have.
So, when flying over an area of an FSDT scenery, if you had the airplane shadows enabled under your control, you wouldn't see the shadows over a certain altitude, but you would still have the performance loss associated with it, THAT'S why that setting is not "optional".
If you *knew* about this (now you know...), you would probably complain that is "annoying" having to constantly remind to turn OFF airplane shadows (that you wouldn't be able to see) on an FSDT scenery to get the best possible performances, and how it would be better if it were "automatic", which is exactly how it is right now.
When you are OUTSIDE the area of an FSDT scenery, the setting is restored as it were, and it's BACK under YOUR control.
For now, I solved this issue creating a .BAT file that every time FSX is started up a new custom FSX.CFG is put, and the previous one deleted.
Totally useless, because outside of an area of an FSDT scenery, the setting will be restored as it was before, and when inside an area of an FSDT scenery, the shadow will go on/off depending on the altitude regardless of what's inside the FSX.CFG, because it will be changed directly in the FSX memory.
Restoring the FSX.CFG would help only in these two cases:
1) You ended a flight when flying over an FSDT scenery on an higher altitude than the threshold where the shadows would be switched off.
2) You saved a startup flight over an FSDT scenery on an higher altitude than the threshold where the shadows would be switched off.
So no, the shadows switching depending on altitude inside the area of an FSDT scenery will not made optional, but we might change the Addon Manager that your original setting would be restored also when exiting from FSX when you are flying over an FSDT scenery, that's the only thing that would be useful.