In our design proces we use skeleton modelling to define parts. Some of these parts in a design are already being manufactured while other features still are in development. The parts and the parameters that drive those features should therefore remain locked. But at this moment it's not possible to lock parameters in a design.
It would be a great addition to Inventor to be able to lock individual parameters from being changed/edited. An extra column for check-marks added to the parameterlist (like the "Key" and "Export" column, see example image below) to lock individual parameters is desirable. Lock Parameter column added
In 2014, this idea was posted but has been archived. I think Autodesk should (re)consider this idea.