Well, according to the dexos site itself, there is dexos 2 and there is CJ-4, which is still the standard for the Duramax diesels in the U.S, according to the dexos2 website itself. Now you figure out, given dealerships and how they do things, if that tech in the lube bay is going pick over details as to whether he drops in a dexos2 or just a CJ-4 that he drops in all the pickup diesels that come thru. I would almost be willing to bet, that those Cruze owners that go in and get their "free" oil changes will have a CJ-4 oil put in and they will not even know nor have any real issues related to the oil. I wouldn't be the least bit surprised they get a dexos1 gasoline engine oil put in by mistake. Now that could be an issue.
I still get the distinct impression that folks are just worrying too much. Those of us that have engines that, by themselves, cost more than most folk's automobile don't sit around and put this much energy into what oil goes in. We just drop in a good CJ-4, of the viscosity the engine requires, the brand we have a preference for (and many times it is not of the OEM "approved" oil list), run the samples at oil changes, and live life in peace. We do not sit around worrying about the OEM voiding the warranty on a $35,000 engine all day long over an oil selection. But, some folks have a lot of time on their hands.