Documentation for impacts with enabled honeypot and site caching
\TYPO3\CMS\Frontend\Controller\TyposcriptFrontendController->isUserOrGroupSet() checks if $GLOBALS['TSFE']->fe_user->user is an array, but this works only if nowhere in the system, data is stored with TYPO3 session handling.
This stores some "ses_xx" keys in $GLOBALS['TSFE']->fe_user->user array. I'm trying to use EXT:staticfilecache which checks for frontenduser with this method and it returns true on every page, because ext:form stores some data in sessions. I'm pretty sure this is not a bug in EXT:staticfilecache.
I used a clean TYPO3 instance only with sysext, EXT:staticfilecache and a fluidtemplate to debug it.