On the dark continent we use “vacating level” calls all the time.
Reasons:
No positive control
Sometimes locally crowed airspace (think relief work) with limited levels available.
Helps:
Lets everybody in a hold stack know where you are and whose next down
Enroute separation.
Hindrances:
People BS’ing on position & time (nahh I hear you say)
Clogged radios.
Overview,
Helps in non controlled environment, other times questionable.
Why?
Preparation for wide area implementation of ADS-B me thinks?
