In twn we have this to prevent spam:
$wgGroupPermissions['*' ]['create'] = false;
However LQT doesn't handle it very well, it keeps asking captcha when trying to save. It should say it is not possible, or allow posting replies to threads regardless.
Version: unspecified
Severity: major
URL: https://www.mediawiki.org/wiki/Thread%3AExtension_talk%3ALiquidThreads/Allow%20anonymous%20to%20post%20to%20liquid%20thread