PDF should be a natural. I'm positive you can disable printing very easily when you generate your PDF file, and there doesn't seem to be any way to use the [Ctrl]+[c] copy to the Windows clipboard because PDF files are viewable only with the Acrobat Reader.
The PDF was developed to enable owners of documents to "securely share" them over networks. That's not an oxymoron as it may seem to be. If a document can be excerpted, it can be easily altered.
Adobe saw a market for paperless access to documents that provided everybody with a degree of assurance that they had not been changed. Since PDF files are encrypted and can only be read by the Acrobat reader, any tampering is immediately detected.
In essence, print enabled Adobe PDF files give publishers assurance that the electronic format isn't any easier for plagiarizers to steal from than an original hard copy.
If a mag publisher disables printing, stealing content would be MUCH harder than with a distributed hard copy. They'd have to screen capture the document, print it out, then OCR it. They'd have to spend a great deal of time to steal low value source material, so the cost/reward ratio couldn't possible benefit them.