Originally Posted by
Shadow Recruit
AIM isn't regulatory, but the amount of times I’ve reported vacating and then had a controller ship me to the next frequency indicates that the vacating call has some sort of use. If they’re swamped I won’t step on anyone to get that call in though.
Point being, there is no "That’s only for a non radar environment in North American airspace." as OP claimed. If it's in your FOM, depending on the verbiage, it is regulatory through that.