I have a 2007 Yukon Denali. This issue started on the passenger airbag side about six months ago and also came up on the top dash driver's side above the speedometer.
I was initially stone-walled at the dealership, called GMC customer care and got nowhere, and finally e-mailed customer care. I informed them that I am a loyal GM customer, and have been for a significant amount of time and that I consider this a defect, which it clearly is, and as such would ask that they fix it as such and repair or replace the dash, regardless of my warranty status (or lack thereof).
I received a call back within about an hour and was told they cannot guarantee anything but that they would try to help solve this problem. They then told me they would contact my dealership and get in touch with me within 24 hours. I contacted my service rep at the dealership to let him know they may be calling and that I was hoping we could get this taken care of and he called me back shortly thereafter explaining that they spoke to GM and could offer me the new part and replacement for a $250 "deductible".
I considered this acceptable, as I equate this to basically paying for labor and getting the part free of charge. Perhaps I could have fought for more, as I see that some people have gotten it replaced for free (although the circumstances with mileage and warranties may vary from mine), but I considered this a fair solution and accepted.
I hope this helps anyone else that may have this issue!