First, locate the hood, second, use the release to pop it. Locate the master cylinder, and the hose running to the engine, cut it. Now the brakes don't work very well. Locate the hose not running to the engine, cut that, now the brakes don't work at all.
Imagine that any person strong enough to operate side cutters can hack into your car and disable the brakes.
With high-tech cars, an attacker could hack every car of the same model. With thousands of Teslas on the road, I think it merits a higher concern than somebody with side cutters.
I thought it was obvious. Next time I'll let it go unsaid..
The attacker would still need physical access like the low-tech attacker to network and update software on the Tesla.
Also, the brake line could be cut in seconds whereas 'jailbreaking' and then flashing the drive control software would take ages in comparison.
even if the software survives a high-speed crash, it's possible for the surreptitiously placed modification to erase itself as its final act. additionally, the surreptitiously placed modification can wait for weeks or months, giving the attacker time to build a cover story or misdirect or accomplish any number of other goals.