Form Validation / Pre-populated input fields

[eluser]intoitdaily[/eluser]
Alright, I'm not so new to codeigniter, but this is the first time I've encountered this issue. So I'm building a form, like normal, in codeigniter. And I noticed that for all the input fields that are to be pre-populated in case of an error found in one of the entries, code igniter won't pre-populate them unless they were required in some way set by the form_validation->set_rules method in its controller.

I don't understand why these features were built in this way. it doesn't make sense. the error fields are not the only ones that should be pre-populated. All the input fields, dropdowns, checkboxes, textareas, etc, should be pre-populated in case any of the input fields encounter an error. My question is, is there a way around this? Maybe I could create my own error_callback function, but just have a pass or something inside it. maybe then they'd all be prepopulated?

Has anyone noticed this before? Am I doing something wrong here?