The defaults will be overwritten if you don't push them in a different namespace.
Imagine having two elements, like
```html
<a 
   data-confirmButton="Yes, delete"
   data-cancelButton="no"
   data-text="Do you really want to delete <strong>User</strong>?"
   data-okButtonClass="btn-danger" class="confirm"
>...</a>
```
and 
```html
<a 
   data-cancelButton="no"
   data-text="Do you really want to delete <strong>User 2</strong>?" 
   data-okButtonClass="btn-danger" class="confirm"
>...</a>
```
Note the missing `data-confirmButton` in the second element. If you click that element first, the button text would be "Yes" from the defaults, but if you click the first element, the button text would be permanently overwritten with "Yes, delete" from that element.

Your defaults would be overwritten by any data-element.

To not have it break current behaviour we could state all the elements twice, old style and new style, at least that would stay cool until someone mixes old style-notation and data-elements together.