allow pre-filled forms to properly dictate Form state

Since recently, it's possible to get a "pre-filled URL" for a form, where some answers are pre-filled using a get parameter. 

However, this does not override values from a previously filled form, if that form as not submitted. For example, if the user has a form half-filled and unsubmitted this state is stored in the browser; and if a link is to pre-filled form is used, only the fields that were empty in the browser state are filled in! 

There may be a usecase for this, but it would be valuable to allow a pre-filled link in such a way that it fully initializes the state of the form. 

Additionally, it would be great to hide certain pre-filled fields from user input. 

Is this possible to do somehow? If not, I hope it'll be implemented.