I think any reputable dealer will want to help a customer that they have sold a car too, surely? The problem here is that the law is very heavily weighted towards the customer but that is because of the stance that the motor trade used to take, that's why a law had to be utilised, so we are currently in this situation because of the bad guys (the Arthur Daleys) 0f the past!
Even if we didn't HAVE to offer a warranty we would! Not only does it protect our customer but also our company from any unexpected problems, which is why they are normally called 'mechanical breakdown warranty'.
If you don't loo after your customers, you don't get referrals and repeat business , without these you are dead in the water!