No - it is a legal requirement that all UK registered insured vehicles be reported on the MID.

The benefits of its inclusion are that it can be excluded from lists used by the police in the detection of uninsured vehicles, that you can easily purchase your tax disc using the DVLA’s EVL system (this system uses MID data to determine insurance), and in the event of an accident your insurance details, along with that of other parties involved, can quickly and easily be identified.