On our electronic credit card machine you can do a charge for a no-show without CVV number. I can't remember how, but we have done it. This only applies to credit cards, and not debit cards. If you choose to accept debit cards they can't be charged for a no-show. On HW the customer gets a message when they book telling them that they have to ring the hostel before midday on the day of arrival to confirm, or the booking may be cancelled.
Apparently you can't charge for a no-show without cvv number in France however - or on a French credit card.