Warning message is written to STDERR.
Use instead of WP_CLI::debug() when script execution should be permitted
to continue.
# wp plugin activate skips activation when plugin is network active.
$status = $this->get_status( $plugin->file );
Network-active is the highest level of activation status
if ( 'active-network' === $status ) {
WP_CLI::warning( "Plugin '{$plugin->name}' is already network active." );
continue;
}