BSD vi/view resets inode ctime: why?

[rex%erebus at adm.UUCP]

Why does 4.2/4.3 BSD vi/view, exited without changing the file, update the
inode change time?  Dump finds many more files to dump because of this, when
the file contents/permissions/etc. have not changed.  This makes incremental
dumps much larger than seems necessary.  Sorry if this has been asked/answered
before, but my access to unix-wizards is sporadic.

-- Rex
   rex at erebus.stanford.edu