If a python daemon thread is still running when the interpreter exits,
it is likely to fail in random ways.

Here is another example, which does not use imports.
I run the script many times, with latest version in trunk, on Windows
XP, debug build.

In the majority of runs, I get an error message:
"""
Exception in thread Thread-1 (most likely raised during interpreter
shutdown):
"""
Other tests seem to show that all modules are emptied by the cleanup
process, but the thread insists to get "time.sleep".

And more interestingly, about every 50 runs, the process segfaults...
I suspect that this is a problem similar to http://bugs.python.org/issue1856