Suppressing Session creation?

Am I correct in thinking that Helma attaches a Session to each visitor 
whether or not I save anything to the Session? If so, is there a way to 
suppress this behavior for a specific page? E.g., if I wanted to 
dynamically generate some badge code--my page output would be getting 
included as a JavaScript or image or some such on someone else's site, 
and I would have no need to keep session information for such requests 
(interesting though it might be for snooping about people's browsing 
habits).

Also, do Sessions just hang out in memory or are they written to disk?

-Joshua