A pdf cannot be copyrighted, only the content (correct me if I'm wrong). As long as the edition can be identified and the logos removed it is legal to add. In copyright law (in the US at least) there is the "sweat of the brow" doctrine which basically says that time and effort does not constitute a copyright. Therefore all the hard work they did scanning those public domain pieces does not mean the have a copyright on the result so they add their logos. (see also copyfraud)Important: This product is licensed for one computer. By opening any of the files on this CD-ROM, you agree to the terms of the license. Click on the bookmark to the left to view the complete license. While the works on this CD-ROM are in the Public Domain, the PDF files are copyrighted and may be printed by the licensee for his/her personal use, but not otherwise copied or reproduced.
I agree. The hard thing about orchestral parts is that players usually don't have a easy access to them (in my experience at least) except when playing that piece. We need more librarian allies who manage orchestra or university libraries. We seem to have at few already. Check out http://www.dundasvalleyorchestra.ca/MemberInfo.html. The librarian there has posted here as homerdundas. In any case it will take time and assuming IMSLP will last longer than before I have no doubts that many parts will show up in the coming years. In the long run I can see having freely available part greatly benefiting orchestras and individuals.One of my past complaints about IMSLP has been the lack of orchestral parts.