Will registered trademark symbol within a URL be bad? I know some special characters are unsafe (#, >, etc.) but can not find anything that mentions registered trademark. Thanks!

When syndicating content, I have heard/read that even if the piece you syndicate has a link back to your site (original post), the engines should be able to tell your post is the original because of the link that is pointing back. Is this the case when the links are "nofollow"? I think not, but I just would like to get someone else point of view. I think that if they don't want to follow the links, they should at least add noindex meta robots tags to the post so it doesn't create duplicate content... Any thoughts? Thanks!