With quotes this:

'It is our expectation that those who use our service with unlicensed or unauthorized third-party clients will likely not be able to log on after Oct. 15,' [Microsoft spokesman] Sundwall said. 'We would encourage those third parties to contact us to work out agreements by which they can continue to have their customers access our network.'

... I think it's tough for MS to say they're fighting for security. That's about $$$ any way you cut the quote.