How do I automatically deselect this option from all posts, without having to edit post by post?

<div class="forminp forminp-onoff_checkbox">
                <input id="a3_pvc_activated" name="a3_pvc_activated" class="a3_pvc_activated" type="checkbox" value="false" checked_label="ON" unchecked_label="OFF" checked="checked">

                <label for="a3_pvc_activated">Activate on this item</label>
            </div>