Web Site Rings

Katra

There is something I am curious about and I wonder if anyone knows.
If you join a web ring and you either change the page where the html code for the web ring should be, or you leave it off your web site, you receive an automatic email to say the web ring code is missing on the web site.
Do the webring companys have a robot that automatically searces the web site or is it done manually by the web ring owner?
If it is a robot, does anyone know what software that would be?

Thanks