I just stay logged in to avoid it.Second year on the forum, and suddenly today the site asked me to fill in the captcha!
Secondly, this is a very outdated bot recognition technology.
The developers are still working to find the optimum balance between preventing spammers while at the same time not hindering our legit members.
Check following the following tool/extension to help limit how often you have to deal with CAPTCHA.
FWIW I installed this extension on my Chrome browser. Once it was installed I clicked each option for tokens to prevent it from happening as much in the future.