Almost no expression of interest ever results in a conclusive "No!".  Consequently, any inquiry from any point in history may be assumed to be from an interested party.  This may sound like semantics, but without clearly expressed PRs in this regard, what are shareholders to conclude?  

Then, "can I look at your data?".  Is that an "expression of interest" which may be used for PR purposes, or is it someone merely wanting to add to their scientific knowledge of the area?  Can anyone ever know the difference?