As advance as the Model 3 is...it is fairly easy to break-into the trunk.
Most modern cars only place the seat release in the trunk or have locking mechanisms. Since Tesla's don't have any glass-breakage sensors or motion alarms...we are going to see breakins like these happen.
It is possible that Tesla has sensors that detects folded seats and can allow the software to sound an alarm...or use the interior camera to detect motion while the car is locked...but as of right now...they aren't any security features to prevent this from happening.
Most modern cars only place the seat release in the trunk or have locking mechanisms. Since Tesla's don't have any glass-breakage sensors or motion alarms...we are going to see breakins like these happen.
It is possible that Tesla has sensors that detects folded seats and can allow the software to sound an alarm...or use the interior camera to detect motion while the car is locked...but as of right now...they aren't any security features to prevent this from happening.