Hi Vahid,
My best advice would be not to share files like that once they are supposed to be locked. Instead use File > Share to create a .sky.zip file and share that. Anyone opening one on a computer will get a copy of the file in a new folder and will not be editing the original. I find this very handy even for just having a checkpoint on a file that I can then spin off various attempts to improve or just play with while still knowing that the master copy lives in the .sky.zip file.
Finally, I will point you to PanoramaWeb.org which we continue to develop as the ideal data storing and sharing platform for data processed in Skyline. Anyone can create a project for themselves, their lab, or any other organization. And by default Panorama manages its Skyline documents in .sky.zip files, as I just suggested you could do for file sharing even without this level of support. But, Panorama was really designed to be this document store, and it even supports document versioning so that you can track various check-points in your data processing.
Hope this is helpful. I don't see us prioritizing exactly the feature you are requesting in the near future. I hope this helps some to relieve the problem you are experiencing sharing Skyline documents without first snapshotting them in a .sky.zip file.
--Brendan