For my 2c, I wish dealers wouldn't call these "Warranties" they are not! They are "Insurance Policies" and as such they only cover the "Insured risks". If it is not on the list it is not covered. And they do not generally cover "Wear and Tear" items. Only "Sudden failure" (And almost any breakdown on a 5 year old car can be attributed to W&T! )
What is more, the Labour hours they allow for jobs are "Tight" (IE No allowance for rusty/damaged fixings etc) and the rates are quite low (£20-30/Hour when I last looked which was a couple of years ago) so I advise customers that the "Insurance" payout should, even if you get it, be regarded as a contribution rather than something that will cover the full cost.
In any case, though the manufacturers wont be shouting about this, 70,000 is about the service life of a DMF clutch (Many don't even last that long). Consider yourself lucky that the failed DMF didnt set fire to your gearbox! (They can you know!)