Disallow Duplicate Submissions

I’ve been looking over the docs and FAQ but haven’t found a solution yet. I have some forms with hidden fields that are pre-filled based on the URL string.

Example: Customer arrives to the contact form from an email to provide feedback on their order using a link like https://skeene.net/survey?ordernum=12345

A hidden survey field captures that order number so I can match the feedback to the order (and other info like who processed the order on my side).

The question is, can I require that field to only allow unique submissions? Like if that customer tries to submit the same feedback again, it would say something like “feedback has already been submitted for this order” (or maybe just a generic “you already sent feedback” or such, I’m not picky).

I know a customer could just change the value in the URL, but this will at least prevent accidental duplicates.