Small tweak to not load JS and CSS for guests as they don't have access to the Messenger anyway.
Hook cssFiles.php:
\IPS\Output::i()->cssFiles = array_merge( \IPS\Output::i()->cssFiles, \IPS\Theme::i()->css( 'livemessenger.css', 'livemessenger', 'front' ) );
to
if ( \IPS\Member::loggedIn()->member_id ) {
\IPS\Output::i()->cssFiles = array_merge( \IPS\Output::i()->cssFiles, \IPS\Theme::i()->css( 'livemessenger.css', 'livemessenger', 'front' ) );
}
and
\IPS\Output::i()->jsFiles = array_merge( \IPS\Output::i()->jsFiles, \IPS\Output::i()->js( 'front_livemessenger.js', 'livemessenger', 'front' ) );
to
if ( \IPS\Member::loggedIn()->member_id ) {
\IPS\Output::i()->jsFiles = array_merge( \IPS\Output::i()->jsFiles, \IPS\Output::i()->js( 'front_livemessenger.js', 'livemessenger', 'front' ) );
}