Fairly Urgent, can someone advise?

I have been asked to send some of our copyright-protected work to a potential customer, suggested method burning PDFs to disk and mail along with accompanying letter/enclosures/contract.

I've prepared the folder for burning, and have locked the first couple of files.

However looking around the internet, I see that locking the files is next to no protection at all. A person could just unlock them, and even if they don't do that, they can still copy text from them, into any other application. I tried that myself with one of the locked PDFs.

Before I go any further, am I wasting my time trying to prevent these PDFs from copying by the recipient? I made the originals using Pages and made the PDFs using print, save as PDF.

Maybe I should just abandon the PDF > disk burning altogether and just send them hard copy? They can't fiddle with that or upload it God knows where.

Many thanks for any help. I have to do this in the next 24 hours.