I have some vague recollection of recent postings about the Guest account pooching the main account (Leopard only). Sorry I was not paying much attention when I read them.
Try a search on "Guest account"
I retain all rights to photo-images I have posted on ehMac. They were posted that other members of the community could enjoy them. They may not be used or sold in any other way without my written consent.
It's Un-Canadian to oppose a warming trend.