Users with restricted files would like to enable guestbook like functionality so that they can find out who and why someone would like to access their data. This will help inform the user on whether or not they should grant or reject access to a file.
This suggestion was requested by a user in our Google Community Forum: https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/dataverse-community/Xn-SsIEaRf8/LwtvL8exXEAJ