Do hotel guests who have not checked out by the receptionist need full compensation?

There is no need for compensation, but you need to accept the punishment stipulated by the hotel system.

Losses caused by employees' faults and negligence shall be borne by the unit. However, if the employee's negligence or fault behavior causes losses to the unit, the unit may give administrative and economic penalties according to the relevant regulations of the unit.

If the hotel lets interns who are not familiar with the business work alone, they must be prepared to bear the corresponding losses due to certain deviations. It is a kind of infringement and illegal to let a paid intern do the work of a regular employee and assume the responsibilities of a regular employee. Even regular employees can't be completely without negligence or fault. The management focus of a unit is to prevent serious negligence and negligence with usual strictness.

Therefore, if the unit really asks you to pay for the room, you can go directly to the labor bureau to complain.