Illegal parking is strictly prohibited in Japan.
If you park illegally, you must go to the police station and pay the penalty accordingly.
If you don’t take appropriate legal action, the car rental contract will be automatically finished and no refund will be provided.
Also, the rental car company will charge you a penalty charge for illegal parking.
If you don’t pay those fines/penalties, ToCoo! may charge those penalty charges on the registered credit card.
Moreover, you will be registered on the list of the car rental company association and you will no longer be able to rent cars again from any of the rental car companies in Japan.