Make certain your property information is updated on booking.com, we usually send a message after the booking letting guests know we do not have a 24 hour reception and request they message/contact us with their estimated arrival time. Once we hear back and we know they are going to be after hours, we send them a message with the after hours procedures. If we hear nothing back and we send a reminder and on the day of arrival we call.
We seem to have found a solution that works for us. We have a 72 hour cancel policy. On the first night within 72 hours of arrival we pre-charge the credit card on file for the amount of room and tax. As it has been our experience 'no show guests' generally book with a credit card that does not work, we then have the opportunity to contact the guest via the Extranet and request another form of payment. In most cases the guest reaches out almost immediately, we are then either given another credit card or we negotiate a reasonable time of arrival and extend a courtesy hold. If the guest does not respond we follow up with a message through the Extranet or we simply cancel the reservation. Very rarely have we had issues as was the case prior to changing our policies.