I disagree with automatic revert unless it requires an explicit flag.

I may have just reorganized my project, removing many files and subdirectories.  Perhaps I forgot to do the 'fossil rm'.  I would not want to watch all of the files and directories re-appear automatically.  I would prefer that a --force flag (or some flag) be required before (possibly many) files (and possibly subdirectories) are repopulated into a working directory.