Tesla (TSLA) has now come up with a plan to allay these fears. Tesla already has a valet mode that limits the driving speed and blocks access to the trunk and compartment. The newest upgrade is a little more advanced.
https://news.alphastreet.com/tesla-owners-can-now-remotely-limit-speed-of-the-car/
https://news.alphastreet.com/tesla-owners-can-now-remotely-limit-speed-of-the-car/