Should the hotel be responsible for the theft of mobile phones and cash when the guests checked in without locking the door and using the anti-theft button?

The hotel is partly responsible for the theft of mobile phones and cash, because the guests did not lock the door when they checked into the hotel and did not use the anti-theft button.

Because of staying in this hotel, the hotel has the obligation to "ensure the safety of guests' lives and property". Now that your things have been stolen, the hotel has at least failed to fulfill its obligation to "prompt" and to patrol safely and prevent thieves from entering.

However, if the hotel has prompted "please store valuables" at the front desk and "please lock the door at night and use the anti-theft button" in the room, it means that it has fulfilled its "prompting obligation" and the hotel only has the obligation to cooperate with the public security to solve the case.

Or give you some compensation, such as exempting your room fee and so on.