Can I trust my C Class?

My Battery/Alternator warning light came on the next time I used the car following a burning smell after I had used a few more revs than I should have. The computer reported 1 malfunction. The local garage (Merc trained but not dealership) said that they couldn't find anything wrong and the alternator was charging the battery as it should do. Do I have a problem and is my car trustworthy?