geekiegeek: Being a business slim desktop I wouldn't expect that any data should be held on it and maybe this is Dells reasoning for not enabling SMART? Its not a server and as a business machine you could reasonably expect it to be connecting to a server for critical files etc.
There is no excuse for allowing a device to fail unexpectedly when that device is capable ok alerting you that it is on its way out so the device can be replaced at a convenient scheduled time rather than when things turn to custard.
I would hope that you have either sold them a server with some form of drive redundancy or moved all of their data to a cloud service and informed them that desktops are not for storing critical data.
The site was brand new to us with this event. Backups are being reviewed later today as a part of a general look at their setup.