So what happens if you try to execute "%PDF-1.<number-between-0-and-7>\n%<4-bytes-above-128>\n" as x86 real-mode machine code anyway? Can't this be modified to

So what happens if you try to execute "%PDF-1.<number-between-0-and-7>\n%<4-bytes-above-128>\n" as x86 real-mode machine code anyway? Can't this be modified to simply undo whatever the PDF magic header would do if it was present?