Bottom line - as with all other instructions, if you can't comply, let us know and at least we can plan accordingly. If you need an extra 10 kts or to slow down a few miles early then it doesn't take a great deal of effort to gain/lose a bit with the following. If, however, you just do it and don't say, then it's back to vertigo's original post and someone will have to go around/otherwise take the delay - more work for at least two of us.
