My colleague and consider this a significant limitation. I agree with the others that once I grant permission to add notes, limiting her ability to tag them is very unhelpful. We are using Evernote to track papers for a course. She is the one adding papers, but I created the notebook so I'm the only one who can add tags. The only solution seems to be to start over and have her create the notebook and the tag list. pfft.
I just ran into this as well. It's a real nuisance for collaboration. Can it please be put on a list of features to add?