This is kind of similar to some of the pdf to latex questions but from a different angle. I'm not looking for a complete LaTeX reconstruction method, I want to know if the comments are safely hidden.
My scenario is that I would like to distribute a sample test to my students which includes the real test or some variation of it commented out---that way I can keep the same file from year to year without having to manage multiple documents. I'm pretty sure that what's commented out is dropped entirely from the compiled document but I'd like to be absolutely certain before I distribute such a pdf. Is there any way whatsoever to extract commented lines from the final pdf? If it makes any difference, I'll probably be using XeLaTeX.