Will the reservation be confirmed?
After reading the Booking.com: Terms and conditions, I doubt if your method works since I believe Booking.com or the hotel might try to charge your debit card the full amount upon confirming your booking.
For certain (non-refundable) rates or special offers, please note that Suppliers may require that payment is made upfront by wire transfer (if available) or by credit card, and therefore your credit card may be pre-authorised or charged (sometimes without any option for refund) upon making the reservation.
What's your aim? To book a reservation with a minimal amount of money? Then the reservation could be created, with a small authorization check as @Tom said. However, as we are speaking about the non refundable rooms, at some moment, usually about a 24 hours before reservation starts, hotel do another transaction for a whole sum or first day payment, and, if it fails, they may deny you to enter before you pay it. Also, you may be asked to present the card from a reservation.
In the UK at least, this payment will probably be put through. If the payment is several hundred pounds, the bank may refuse the transaction, and will probably put a security block on the card. If it's £50 or so though, almost certainly they'll allow it.
Your account will then be overdrawn by the cost of the deposit, and you will be charged for setting up an unagreed overdraft. The charges these days are less than they used to be, but you will still be charged. And of course you'll incur interest on the amount you're overdrawn and the charges, for as long as you're overdrawn.
In short, it's not a smart move.