The option to no longer support IE6 is something that crossed my mind as well - some time ago. Like a lot of developers I hate IE6.
On sites where this is possible (non-customer sites), I put in a friendly warning to stimulate people to upgrade. It's about time!
But, to crash someone's browser on purpose seems malicious to me. I wonder if it's OK to actually provide a plugin for that.
Just my € 0,02