Python's methods on unicode strings also apply this logic. E.g.:

     >>>  u'١٣٦٨'.isdigit()
     True

    >>> int(u'١٣٦٨')
    1368

I suppose this could be potentially abused if you are storing and displayeing what is supposed to used as a number as unicode text, but later convert it to a number. E.g. an online shop where you are asked whether you want to pay '5꯸' for some item which looks like 5 plus some weird square, but is really int(u'5꯸') => 58 -- http://www.fileformat.info/info/unicode/char/abf8/index.htm