You can now bypass the login CAPTCHA by bookmarking the link generated for you here:
https://bitcointalk.org/captcha_code.phpIf it causes problems, I might restrict it to Jr Members and above or something, but currently anyone can do it.
Apart from this solution, if you have trusted machine then do not log off from Bitcointalk.
I do not log off from forum as no outsider has access to my machine but maybe do not work well for others.