Disklavier

I am in a unique situation, about to trade disklaviers with another 
owner, my piano is 4 yrs old, and his is 1 yr old.  The trade makes 
sense from all perspectives to us, except for Yamaha's position that 
warranty is not transferrable.   This is a concern for both us of, in 
the unlikely event that either piano would be needing warranty work.  
We are both assured by our respective dealers that Yamaha always 
stands behind their pianos, whether first owner or second or 
whatever.  But the official answer from Yamaha is that warranties are 
not transferrable.  We are just mystified why Yamaha would reportedly 
stand behind their product but still refuse to formalize a warranty 
transfer.   Cars, boats, etc, etc , all have transferrable 
warranties.  A disklavier is a big investment whether first or second 
owner.  Why would a reputable company like Yamaha take such a 
negative position with their customers?
 
Curious if anyone has had experience which would shed light on this 
bizarre situation.  That is, can you shed any light on whether this 
warranty transfer question is a big deal or a non-issue for us?

Thanks.  

Dave