ML tower clears all departures to 5000. When transferred they usually get unrestricted climb to FL240 or their planned level if lower.
I have joked in the past that ATC forget that aviation is 3D, but this sounds like it is true.
Does this mean that altitude is not normally used for separation, and aircraft at different altitudes will not be permitted to cross paths without horizontal separation?
I'm guessing that levelling off at 5000 is not usually necessary, so FL240 is given before 5000 is reached. This means clearance for a 20000' block of airspace, which certainly would make it difficult to get other aircraft through.
It makes sense to clear directly to high levels if there are no conflicts, but perhaps when there are other aircraft wanting to transit the airspace a more specific clearance might be helpful - either above or below the other aircraft path.