@Yutaka7
What @Sarah977 has said is quite correct but many times it is a case of 'terminology'!
There is a vast difference between Inquries and Requests.
Inquiries:
You will never be penalised as long as you 'respond' to an inquiry...you don't have to accept it or decline it because all it is, is a question from a prospective guest, nothing more!
If a part of the guest inquiry is the request for a pre-approval......that will require a 'Grant/Decline' response on your part, and you will not be penalised as long as you do not decline too often. If you declined more than 4 pre-approval requests in a 6 month period you would receive a penalty advice notice from Airbnb. Once you have granted a pre-approval there is no further action required on your part. The recipent of the pre-approval has 24 hours from the time the pre-approval was granted to proceed to a reservation request. If the guest does not proceed in that 24 hour time-frame the pre-approval lapses and the whole inquiry drops off the system with no penalty to anyone!
Requests:
A reservation request however does require an 'Accept/Decline' response from you within 24 hours and a failure of you to respond will see the blocking of your booking calendar for the requested dates and your 'Response' rate stats will be affected. Once again too many declines will result in a penalty notice which may go from a warning to the temporary removal of your listing for failing to meet hosts standards.
Response time is important to you and your response time will be displayed on your listing description where it will be shown as anything from 'Less than 1 hour' to 'Within 24 hours'
@Yutaka7 one thing to remember, as a superhost you have a dedicated superhost number to call for rapid support and provided you call that number from your registered Airbnb phone you will be connected to the first available CS in the world wherever that may be. Response time is rapid and if ever you are in a situation where you do not feel comfortable with a reservation request, call CS and get them to deal with it. If CS handle a decline or a reservation cancel it will be regarded as neutral and have no effect on your stats
I hope this is of help to you Yutaka.
Cheers.....Rob