Parameter blocks are reference targets (ReferenceTarget). A 3ds Max object always derives from ReferenceMaker, and one of its reference is the parameter block. Most of the time, a plug-in object is the only ReferenceMaker that will reference a parameter block.

This means that when your plug-in creates a reference to a parameter block (see Creating and Changing References) it will be saved and loaded automatically by 3ds Max when the plug-in is loaded or saved. This also means the deallocation of the parameter block is taken care of automatically, once there are no more ReferenceMakers that refer to it.