I just purchased a 2010 M6 convertible with 28,000 miles over the weekend and as I was pulling out of the lot the issue came up where it said top not locked and the trunk would not open. The dealership held onto it until Monday when their service tech came in and fixed it so I went to pick it up. Was driving on the highway today when about 15 minutes in it popped up again and said reduce speed top not locked. Went back home and it has fixed on its own. I took the car to an M specialty mechanic before purchasing it and he said it was a clean car. I have not attempted the fix with an allen key or by pushing the rear sensor because it has fixed on its own. I have until tonight to return the car for a full refund and was hoping to get some opinions. If the issue has popped up twice in the last week should I be worried and bring it back? It seems to be a common issue with a fix that can be sometimes quick and easy or sometimes expensive and a pain.