On Fri, 27 Apr 2018 22:46:50 +0100, "dennis@home"
wrote:

Do you think its legal to drive a car that you know will fail the MOT?

Yes it is legal

They can prove you know if the fault has been cleared without the
diagnostics being run.

Would love to know how anyone would actually perform this action

Unless you know why it came on you don't know if the
airbag will deploy when it should or if it will deploy when it
shouldn't. You would look pretty stupid if it went off while you were
doing 70 on the motorway or leaning over to clean the screen.

The built in precautions to prevent accidental deployment of an airbag
also ensure intentional deployment