The documentation for os.utime() at http://docs.python.org/py3k/library/os.html#os.utime states:

"Set the access and modified times of the file specified by path. [...] The effect is similar to running the Unix program touch on the path.)"

Unlike 'touch', os.utime() will not create an empty file if called on a file that does not exist.  IMO the current behavior is correct, but the comparison of os.utime() to touch implies that it would create empty files.

I suggest clarifying the documentation to emphasize that os.utime() will not create new files and raises OSError in the event that the file does not exist.