At least in Python 2.4 shutil.copy2() not only copies content and 
access times of a files like stated in the documentation but also the 
access bits.

That behaviour I would not expect because in other functions from 
shutil it is explicitly stated if the access bits are copied.

In fact I used
    shutil.copy2(src, dest)
    shutil.copystat(src, dest)
up to now. What does not work if the read-only attribute is set and 
what is completely nonsense after having a look into the implementation.

This seems to be a documentation issue.

"""
shutil.copy2(src, dst)
Similar to copy(), but last access time and last modification time are 
copied as well. This is similar to the Unix command cp -p.
""" -- http://docs.python.org/dev/library/shutil.html#shutil.copy2

Does not mention permissions while

"""
$ pydoc shutil.copy2
shutil.copy2 = copy2(src, dst)
    Copy data and all stat info ("cp -p src dst").
"""

implies that the permissions should be copied.

Maybe the documentation should simply recite the implementation: copy2 
is copyfile follwed by copystat.

Thanks, fixed in r63369.