Is there a simple way to hang a virtual "Out of order" sign?

RouterOS Beginner Basics
2

This thread has a few approach to a similar problem:
http://forum.mikrotik.com/t/a-very-simple-redirect-to-an-http-page-after-join-wifi/165960/1

Basically the options from that are:

  1. Create a [largely unused] captive portal on new VLAN, with update HTML with your “Out of order” sign. For maintenance, you change the VLAN to captive portal VLAN. The only issue is /ip/hotspot does add a shit done of dynamic firewall rules, which might gets annoying when reviewing the config.
  2. Do the same, but same old/cheap Mikrotik to have to run just the captive portal with "Out of order’ HTML, and plug in the small router. This has the advantage if the router itself was broken, you can still have have your “Out of order” flag flying. Since the hotspot does little and traffic to one web page is light, even some older mAP might due & it it could be plug-and-play.
  3. if you already have a local web server, you can using set DHCP Server to return a custom option with the link to a web server (with HTML and JSON file for the DHCP Option). It take half the lease time on average for this method to trigger, but a bit simpler than enabling the full captive portal.