It has been well-documented that a stranger can open your car with the wrong key/fob/phone.
In this Vancouver case, the police were also called, so it's not fake!
Vancouver man claims he accidentally opened door of identical Tesla and drove for several minutes before realising error
www.carscoops.com
This thread is not the first case. Tesla has not addressed the issue so don't expect the case to be solved soon.
While waiting for a solution, you can start using the PIN-to-drive. A stranger's key/fob/phone can access your doors but not the glovebox or propulsion system without the correct PIN. Most likely, the stranger's PIN and yours are different. But if both of you use the same Year of Birth like 1970, then that won't help either!