
So a simple suggestion - to skip file copy over its hard link, also if user tries to move file over its hard copy, TC may just delete source file - because these files really the same!
Of course, TC should do this check only if OS doesn't allow to open target file. And, if TC sees that files are on the same drive and have same file system ID, it may safely skip operation (for copy) or delete source file (for move).
BTW it is good that OS doesn't allow to open file twice - else TC will reset file contents while copying.
To compare indexes of files TC may use GetFileInformationByHandle function and compare nFileIndexHigh and nFileIndexLow fields of returned structure for both files. Function is available under Windows 2000 and later.