Reasonable use of _hidden

The context is a mvc application which uses unobtrousive validation.

Using a custom format submit the value (and the name of the input) is moved to the hidden input.

This behaviour breaks the validations, so 2 changes to the hidden field are needed:

1) copy all the data-val information to the hidden input
2) attach a class to the hidden input that could be used as selector to remove the hidden field from the ignore list of jquery validator