In its 10-K annual document, Tesla notes: "If our vehicle owners customize our vehicles or change the charging infrastructure with aftermarket products, the vehicle may not operate properly, which could harm our business." The company has referenced "automobile enthusiasts" who want to hack their Tesla to improve its performance, warning that those who do may compromise the safety systems. It says some customers have modified their position in the driving seat, which reduces the effectiveness of the airbags.

"We have not tested, nor do we endorse, such changes or products. In addition, customer use of improper external cabling or unsafe charging outlets can expose our customers to injury from high voltage electricity," says Tesla. "Such unauthorized modifications could reduce the safety of our vehicles and any injuries resulting from such modifications could result in adverse publicity which would negatively affect our brand and harm our business, prospects, financial condition and operating results."

Even though Tesla is rapidly growing its customer base, the company is still a minnow in a big automotive pond. Because it's also helping to drive the adoption of electric cars, it has also had to deal with questions over safety, following reports that some of its vehicles caught fire after being involved in an accident. Tesla basically has to keep admitting that it has no control over what its customers do with their cars, but knows that if some plucky tinkerer touches the wrong wire, it will be the one who has to deal with the fallout.