> The case where the letter looks the same (at least in my email) but is
> apparently different may require some thought, too.

In case it's useful, when I do a list(map(ord, ...)) on those two 
lookalike strings I get (where 'expected' comes from the explicit .decode, 
while 'found' comes from listdir):

expected: [102, 111, 111, 246, 98, 97, 114]
found:    [102, 111, 111, 111, 776, 98, 97, 114]