Tesla factory boss defends knocking on workers' doors when they're off sick at home

• A Tesla factory boss defended the decision to knock on workers' doors when they are off sick.
• André Thierig denied the home visits were unusual and suggested workers were exploiting the system.
• High rates of absence at the factory have attracted the interest of Elon Musk.

The boss of Tesla's German factory has defended the decision to send managers to knock on workers' doors while off sick.