I expect I'll get flamed for this - but when asked to slow down we try to comply as tardily as we think we can get away with (similarly, when asked to descend too early for optimum profile).
Margins are so tight in corporate flying at the moment - the only profit we make per flight is what fuel we can save compared to that budgeted on the flight plan. In our company we are desperately trying to keep the company afloat and keep our jobs - so if we can save 50lbs of fuel, we'll fight for it.
If you think somebody is taking the mickey, just say the magic words - "slow to xxxknots, or expect a hold at yyyy"!