[chii]

> Cancel could also be implemented by hiding a UI element, for example.

Sometimes this can be confusing, because the hiding of the UI element doesn't prevent the submission of the form later. If the page is a giant form, with individual parts made to look separate (such as a large tax form), the cancel merely hiding the edited element (while retaining the data) means a later submission could inadvertently submit the data that was intended to be cancelled by the user.