I understand your point...
However, I am not condoning any sort of illegal activity. In fact, allow me to clarify something. The reason why these PDFs I worked with were secure in the first place was so that you could vouch for their authenticity. But, If you were circumventing the protection in order to ease importing into... say a database which could choke on encrypted content in a PDF, then that is most definitely above board.
I used to work for a company that uses the IBM DOORS system for requirements management. In this scenario, I was tasked with importing PDFs from various sources (the IEEE consortium notwithstanding) and we were given the license to do whatever we needed to do with the documents, so long as they stayed internal on the company servers. This included getting around the document security if it was necessary to help facilitate in a clean database import. Keep in mind, with the PDF to XPS to PDF trick I employed, I helped to save the company money on paper that would have otherwise gone to waste printing the secured PDFs to a physical printer and scanning them back in, which is what all the engineers were doing at the time. Not to mention, the printers were few and far between and backing up the print queue because you wanted to print a nearly one thousand page document to rescan wasn't something I considered courteous to my other coworkers.
In closing, just use your common sense in situations like this. I am only attempting to make life easier for engineers... not suggesting that you forge documents. Besides, if you were thinking of pulling a fast one by repackaging the document, you would still need the original root cert used to digitally sign the PDF, which you wouldn't have access to in the first place.
Contributr 
