As previously mentioned makkan, BMWs hands are tied re: what they can do to lock out the OBD port. If they put a layer of encryption between the port and the ECU then a thousand and one independents and their customers are going to be rather unhappy. And there are EU regulations in force to stop them doing just that. If ways around that encryption are then supplied to said indies then obviously that will get out and we're back to square one.
I'm not sure if I have contributed to this particular topic but my view is there is a certain amount of hysteria and to a point I do sympathise with BMW. I don't think this problem (or widely available tech know-how) did exist in the years that the E9x was in development and during it's early production. The major failing as I see it is in BMWs poor security system for RHD cars and the fact that they haven't acted before now to do something about the sensor coverage. That obviously means the so-called upgrade will focus on as Hotcoupe says 'the alarm, the sensors and the blind spot'. Unless I'm completely misunderstanding things that's the only thing BMW can do.