I have, admittedly, skimmed through this quite long thread, so forgive me if I repeat anything someone else has already said.
To the original point: if pilots are instructed to do something while under radar control then they should comply unless doing so would endanger the aircraft. I can't, for a moment understand any pilot deliberately not flying a speed as instructed, but I know that wasn't the original point. That was telling the next sector your speed.
I think this is not a deliberate ploy and I realise the original post was a 'gentle' reminder. I've often thought we have to tell the next person too much and I wonder how much of that they hear. Could it be the controller didn't hear it?
Although it's not necessarily absolutley correct, due to the niceties etc a typical call could be: "Morning Director, Speedpig 533, flight level 105 descending flight level 80, radar heading 280, speed 280, Airbus 320, information Golf."
This is quite a common mouthful to have to spit out and I'm sure it's obvious why some things might get left out. Equally the over-worked director might only hear the bits he really needs to hear (who and where they're going) so the speed might get 'missed'.
You guys and girls do a great job and we certainly don't try to make it harder. Most of us are pretty normal humans and screw things up, such as radio calls, like the best of them but I still reckon the Brits are the best in the World...both sides of the 'scope
That should get the Shermans going......
And.....
Recover
PS: what's the name of the really nice LGW Director who sounds like the 'Suit you' blokes off the Fast Show? "Good day, Sir....oohhh"....makes me laugh every time