Have at it… I have attached a document using Docuprinter. Use your vast hacking skills to modify it and I mean the document itself, not some cut and paste special.
I have never had a problem with it. You can add security features somewhere in Adobe.
If someone really wants to, they can break the security. There is a program called pdf unlocker which can do that very easily. There are several others as well.
I think what John was referring to was people sending out reports just as the form came to them, except filled out.
I also know of some form designers that have made forms which allow you to print the document, so they could be “acquired” then filled out, then printed to a pdf, or, if you wanted to you could take the form, scan it as a pdf file, then modify some things.
As I said, if someone has criminal intent, they will figure out a way to do what they want.