I drive down the M42 quite often, the hard shoulder is indicated to use for the next junction only which might be 2-3 miles further on, so you find yourself driving along at 65-70 and suddenly someone undertakes you and shoots past on the HD doing 75 or whatever and you think to yourself what happens if I suddenly have an engine problem,a tyre blow out or whatever and need to coast onto the HD?
You coast onto the hard shoulder and run away from the car as quickly as possible, then you hope they see you on the cameras and change the signage. They are changing the M27 here to smart motorway, 4 lane running with no hard shoulder only refuge points at set distances so tough luck if you have a problem away from a refuge area.