Hmmm is incorrect. Controllers do not have authority to waive the 250 knot speed restriction, except where expressly authorized by the administrator. It is not at the discretion of any individual controller.
A controller who provides a verbal clearance to exceed this speed retriction is not authorized to do so, and following this clearance does not protect one from enforcement action. Following Hmmm's advice can lead to unpleasant certificate action.
One must assume that Hmmm is a flamer, else he understands very little of the regulation, and it's attendant legal interpretation.
I also represent the administrator, and have NO authority to interpret the regulation, nor in any way to authorize deviation from the regulation. Go figure.