Very few of them are going to buy the product, thus not supporting the writers, artists, marketers, designers, distributors and retailers that brought you that product you just got for free.
Except that, of course, we can't ever know what effect PDF piracy has on actual print copies being sold.
Amongst my group of peers downloading PDFs of products not yet bought more than 75% of the time leads to the hard copy purchased at the FLGS (so no amazon discount) The other 25% of the time we find the product not to our liking and not of use to us. I seriously can not fathom any group of people who game like we do all sitting around with laptops to read a pdf while gaming rather than passing a book.
So in our circle (and I highly doubt ours is much different than most except that we very rarely buy more than one hardcopy of a book as we prefer to share our books and thus buy more titles) a downloaded PDF leads to MORE sales of hard copies, and supports our FLGS
Black's Law Dictionary said:
Theft is any of the following acts done with the intent to deprive the owner permanently of the possession, use, or benefit of his property
Deprive the owner Permanently of the :
1. Possession: Nope wotc still has possession of exactly as many as they had possession of before. If I uploaded a virus to WOTC that deleted theirs after I made my copy then they would no longer have possession
2. Use: No they can still do everything with it they used to be able to. If I had it redacted, made it non transmissible, or corrupted it so it couldn't be opened then they could claim that they could no longer use it.
3. Benefit: This is the strongest case to be made however to make it you need to show that they were harmed in some manner. The benefit they hope to incur is obviously profit from the sale of the PDFs. So then the questions are : (and I have yet to see good answers for any of these)
A: Would the people that downloaded free illegal PDFs had ever spent the money on the legal ones ?
B: Did the downloads of illegal PDFs negatively impact PDF or Hardcopy sales ?
C: Did the downloads of illegal PDFs positively impact hardcopy sales (yes even I won't try to argue that it would have increased legal PDF sales) ?
D: Did any positive impact to hardcopy sales (either via browsing of a pdf then hard copy purchase, or exposure of the hobby as a whole) outweigh any negative impact ?
E: What has this whole issue and the handling thereof done to community of hobbyists both in regard to how we see ourselves and WOTC and how the outside world views WOTC and the hobby/hobbyists ?
Black's Law Dictionary said:
with the intent to deprive the owner of the benefit of ownership (or possession) permanently.
I doubt anyone could prove that anyone else "intended" for people that desired to buy the PDF to be unable to do so. They can still sell to everyone that prefers to buy from them as they still have possession of all of the property they previously had possession of. Seeing as how your source also state it has to be done "permanently" are you saying you would be okay with PDFs that were unauthorized but self deleted after say 99 years ? They wouldn't be permanent.