This might just add unnecessary bloat, but since Python is being 
used in CGI scripts, it can be used to narrow a security hole. One way 
of breaking security is for a naiive programmer (don't try to deny 
their existance) to run an arbitrary command from the page 
viewer.

Perl has developed an interesting mechanism for 
helping with this: taint. The way it works is, when something comes 
directly from the user, like a key in a form, it is considered to have 
taint unless specifically untainted. Things like os.exec() would 
create a warning message if you passed tainted strings to 
them.

As I said, this might just add unnecessary bloat, but for 
an option that can be left out for most builds of Python I think it 
would be pretty nice.