Delay the ability to publish posts

delay_publish.php

<?php
/**
 * Plugin Name: Delay post publishing
 * Plugin URI: http://unserkaiser.com
 * Description: Only allows publishing a post if the user registered one week ago. 
 * Version: 0.1
 * Author: Franz Josef Kaiser
 * Author URI: http://unserkaiser.com
 */
// Not a WordPress context? Stop. Why? Ask @toscho
! defined( 'ABSPATH' ) AND exit;

// Only run this for new "post"-post_type admin UI screens
if ( ! is_admin() AND 'post-new.php' !== $GLOBALS['typenow'] ) return;

function debug_user() 
{
	// User data as object
	$curr_user = get_user_by( 'id', get_current_user_id() );

	// get time/date and format as UNIX timestamp
	$reg_date  = abs( strtotime( $curr_user->user_registered ) );
	$curr_date = abs( strtotime( current_time( 'mysql' ) ) );

	// Human readable difference
	$diff       = human_time_diff( $reg_date, $curr_date );
	$diff_array = explode( ' ', $diff );

	// Remove if we're on the 1st day (diff result is mins/hours)
	if ( 
		strstr( $diff_array[1], 'mins' )
		OR  strstr( $diff_array[1], 'hours' )
	)
		return remove_meta_box( 'submitdiv', null, 'side' );

	// Remove if we're below or equal to 7 days (1 week)
	if ( 7 >= $diff_array[0] )
		return remove_meta_box( 'submitdiv', null, 'side' );
}
add_action( 'add_meta_boxes', 'debug_user', 20 );