(no I don't even trust them to submit their name manually)

My employer has at least one form like this that takes employee number, then autofills my name and then dies with an error because my name is too long...

More on topic: there are several modules that let you work with PDFs - the simplest thing to do is probably add your own timestamp or form ID to a submitted form, rather than extracting out all the details of the form. Adding a stamp should be relatively simple (I've gotten that far with PDFs). Extracting all the details requires that you anticipate all the possible things that can do in generating a new form, possibly to the extent of reverse engineering the form generator.