Some nodes don't have code but give good background info on general programming "HOW TO" and perl specific implementations of common techniques, so I wouldn't just drop them.
But the Idea about PDF is quite good as there are also references to the Adobe API's available from Adobe and modules on CPAN to access those, so it's easy to make a printable book out of that using Framemaker or Distiller.
On the other Hand some might agree that it is within perl's tradition to make such book available for free download as well.
I might have misunderstood the term "Flag".