Why not ?
For sure, I understand that DrivePool is not an antivirus but I think it could be quite simple to implement a optional feature that could block any process (inside the NAS or external thru the shares) that try to create a .encrypted file (suffixes taken from a configurable list.....). Blocking this process, DrivePool results to block any tentative to manipulate the original file (supposing it FIRST create the encrypted one, then delete the original).
About the rest of the comments: I'm quite confused .... when I was on Windows Home Server all the suggestions was to NOT use a