They potentially could be.  However, if the result is something like
>>> if a:
    if b:
        print(a+b)
or worse, with Lucida Sans Unicode, the visual equivalent of
>>> if a:
  if b:
    print(a+b)
then I do not find result very satisfactory.  I think moving the prompt to a sidebar, as with line numbers (forthcoming), is a better solution.  This will make code look good both in the shell and when copied and pasted elsewhere.  I hope to have a patch in a month or two.