While performing inspections, you often need to reference other materials. Other source code files, Requirements and Design documents, etc. Currently Collaborator has no way to include these as part of a review.
If you upload these reference documents, they become part of the review. The only other option is to create a custom review field and use the text field to tell people where to find the reference material. (We ended up zipping up reference material, checking it into SCM, and putting a link to the zip file in this custom text field.
It would be nice to have a more elegant solution to include reference materials in with a particular review. Ideally, a way to upload these files but not make them part of the review itself.