The reference to "exceptional circumstances" comes from the Aer Lingus
PR guy who said that such circumstances are those in which the 10-hour rest would be used.
As for hotel rest, the minimum rest allowable by CAP371 is 11 hours. This must be extended when the journey time between the airport and hotel is more than 30 minutes each way.
With regard to your final paragraph, I agree absolutely with its main thrust - this is NOT safe.