confused by STATUS ON/OFF purpose

[Nathan Vander Wilt]

I'm trying to figure out what a layer's "STATUS" really means. I get  
DEFAULT -- basically, the layer is on no matter what. But in  
practice, I'm not seeing the difference between ON and OFF.

http://mapserver.gis.umn.edu/docs/faq/default_vs_on_vs_off has a  
promising description, but doesn't seem accurate either.

When I query layers=all, I get layers with both ON and OFF status,.
When I omit layer/layers from my query entirely, I don't get any ON  
images, just DEFAULT ones.

What CGI query will return the layers with ON or DEFAULT set, but no  
OFF layers?

thanks,
-natevw