Silvaire,
there is a similar bulletin, the
Cessna secondary seat stop modification. For pretty much every piston plane ever built (starting 1948), Cessna will pay for time and material to install a secondary inertia reel to prevent the pilot seat from sliding back should the seat stop system fail. They have been offering this for several years but most planes still don't have it. There is no AD.
If I rent out my plane and the primary seat stop fails during takeoff, the seat slides back with the pilot holding the yoke, plane stalls and everybody dies -- what is going to happen? Wouldn't some contingency lawyer go after me because I haven't installed the secondary seat stop modification?
The same danger probably also exists with the SID. As long as you don't let others fly your aircraft, there probably isn't much danger but as soon as you do (even for no charge), you might be at risk.