We noticed that the SIT_FLAG_INVISIBLE flag was not implemented as proposed by Signal on https://feedback.secondlife.com/scripting-features/p/add-llsetsitflags-sitflaginvisible-et-al .

We were hoping to have this implemented to make the avatar invisible so it would not require detaching all objects and wearing an alpha layer so you would not be rendered in smaller vehicles. It affects interacting with vehicles in a FPS setting when multiple avatars are on the objects. (For example, Avatars in the Commander Seat, Gunner Seat, and Driver Seat)

This would also allow us to scale down vehicles without considering avatars rendering and ruining the immersion.