Can I disable syncing when WordPress users create accounts?
You can unhook CiviCRM's hook callbacks like this:

add_action( 'plugins_loaded', 'my_disable_civi_user_sync' );
function my_disable_civi_user_sync() {
    if ( ! function_exists( 'civi_wp' ) ) return;
    remove_action( 'user_register', array( civi_wp()-&gt;users, 'update_user' ) );
    remove_action( 'profile_update', array( civi_wp()-&gt;users, 'update_user' ) );
    remove_action( 'deleted_user', array( civi_wp()-&gt;users, 'delete_user_ufmatch' ), 10 );
}


Disclaimer: this is untested code. You may need to hook into a later action, e.g. init.