one additional thought...as pilots we have all experienced the need for SPEED restrictions.
at certain airports, for example that 747 chap going into EWR, after the first time you are hosed by atc in this sort of rude manner, next time you make your initial call to the facility, simply:
Approach control, Callsign, level at 4000, NO ASSIGNED SPEED.
of course a wise guy will say, DO YOU WANT A SPEED ASIGNMENT?