Aviater - Depends on where you are in the world. Yes, in "nervous" EASA-land and Australia, where the CAA's can be convinced to allow killing small children if it could somehow improve safety by 1%, they will be mandatory (of course). SID = AD's in those countries. But in FAA-land for part 91 operations, they don't. You don't even have to follow SB's if you don't want to.