Totally untrue and nothing but a marketing ploy.. So long as the oil you use meets or exceeds the manufacturer's SAE recommendations you'll be fine. I don't waste money because I think one brand is better than another. I have never had an oil related failure in any of the cars I have owned.
I finally ceasing vendors claiming they meet or exceed GM specs which they never had GM test
GM changed the policy 5 years ago that to maintain warranty the oil had to be on GM's certified list which many of the oils marketed are NOT which means they are also not GM approved.
To deep six all this GM has come out with a new oil standard called dexos and all 2011 cars will have to meet.