From the original thread an interesting point was made on these clearances. A little "thought experiment"
If the ATC instruction was misheard by the pilot, there is no cross-confirmation by ATC that the pilot has made an error. Example, ATC has conflicting traffic underneath and for planning asks pilot to report "top of descent", pilots discussing next EBA, both think they heard "leave on descent" and quickly read back callsign only, set the level bug to lowest safe. Frequency chokes up as said aircraft start descent and only after passing the next two levels report descent to ATC.... get the picture? What happens at ATC's end - immediate stand-down of controller(s) involved pending investigation of level bust.
And here's another required readback:
CLEARED VISUAL APPROACH
same reason!