Additionally, it would be preferable with a means of applying an ID and/or purchaser's name to one of the book's first or last pages to discourage people from throwing up the e-book on a sharing service
- I could just remove the first/last page.
- I could overwrite the ID/info
- I could run the PDF through OCR software to produce a new untagged PDF.
Unfortunately, ebooks and piracy go together like bread and butter. PDF is a portable document format and epub is just text. Your best bet is just to make it as pain-free to purchase as possible.