It's not so much that Tesla believes there's a problem but they want to get out in front of this and solve a "problem" that might affect sales.
So you're in the market for a Tesla. You go to the showroom and talk to one of the Tesla people and you mention that you've heard these electric cars can catch fire in accident. The salesperson says, "Well, statistically, there's no more risk of a fire in an accident than there is for a gasoline powered car."
Yeah, right. Salespeople are really trustworthy. "Statistically" means you're lying to me (Lies, damn lines, and statistics).
So you're in the market for a Tesla. You go to the showroom and talk to one of the Tesla people and you mention that you've heard these electric cars can catch fire in accident. The salesperson says, "Well, what we at Tesla have done is added a Titanium shield--the same kind of material the US Government uses on armored vehicles--over the battery pack. Furthermore, we've added an aluminum bar and extrusion so that if the wheels come flying off after you hit a roundabout at 110 MPH the battery pack won't get damaged."
Which answer, as a customer, are you going to feel more comfortable about?