since if there is no action from booking.com site, we should opt out from booking.com maybe just use agoda.com instead...
why want to remove from booking.com? any bad experience?
my suggestion and current practice is ask for deposit. if there is no deposit given then the booking is not confirm even booking.com say every booking is confirm.
you can do it in calendar section, click the date you wanted to changes.
my suggestion is you ask for deposits after the booking made. If the guest are not paying for deposit let them know their booking is not confirm. that is my current practice.
what i do is ask for deposit, if they cancel within 7 days of the booking date. The deposit are not refundable.