Why do you consider a portscan to be an attempt to gain unauthorized
access to your computer?
The management of the portscan it's really a pain, i got my server on Hetzner.de disconnected again due to portscan getting out from my TOR exit node.
We *really* need to find a technical way to be able to detect and block outgoing portscan from the TOR exit nodes.
As Tor exits are a curious mix of common carrier and end user in this case... If of concern, I'd simply suggest the application of an IDS and blocking system to your exit traffic. Bro, Snort, filters, some other applicable system, whatever it may be. There is certainly precedent for doing so in a common carrier agnostic fashion in other areas of the internet, no reason that Tor must be any different. And no reason that such application would have any adverse affect on the underlying principles of Tor to which we all might ascribe.