Depending on how the merchant has their app configured, there are two possibilities:
For some merchants, you get charged at the time of checkout, and if your recipient does not accept the gift within 10 days, you will automatically receive a full refund.
Some merchants have the “Deferred Payment” option enabled, which means you will not be charged until the recipient has accepted their gift. In the case of bulk orders, you will be charged for only the recipients who have accepted their gifts.