Ras1: The typeset scores you mention fall into sort of a nasty gray area as far as how I've been treating them at IMSLP. Strictly speaking, if they are mere retypesets, with no significant editing added, they are public domain in most countries. However, there are several countries (UK, Germany, and France - maybe others) that recognize a copyright for the typesetting and page layout itself.
Mostly out of courtesy, I've been assigning Creative Commons Attribution status to those from well-known sites that have free, unlimited downloads of such items, like Mutopia and WIMA. It gets a bit more problematic with files from other sites, especially the ones that make all sorts of claims of copyright, etc. If you download the file free of charge and correctly credit the typesetter, assign "Creative Commons Attribution 3.0" for the copyright status, I mark it as "checked" status unless there is some compelling reason not to - like a new transcription of arrangement, or complaints from the typesetter. A while back, I uploaded files from the Gilbert and Sullivan archive that were mere retypesets of public domain scores. The G & S site complained and we took them just as a courtesy.
Feldmahler: I suppose the potential problems that arise with the trademark issue has to do with 1) the necessity of copying a file (and embedded trademarks) in order to upload it or even e-mail it as an attachment; 2) the possible violation of trademark law by actually removing a trademark from the item. This will take some more lookng into. I don't know how strictly Canadian law treats such embedded trademarks. Another wrinkle might be that using a trademark in such a manner constitutes an attempt to secure copyright on a public domain item that may not be the physical property (virtual property?) of the trademark owner to begin with. At least in the US, some courts have held that such "backdoor" attempts to protect something that is normally the subject of copyright statutes is an invalid use of the trademark.