[Stage3]

My girlfriends iPhone has started acting screwey lately. It's been happening for a while now and has been happening before updating to 3.0. What's been going on is that her phone switches from her iTunes account to my iTunes account without ever being synced. I've searche and found out that apparently, this just "happens" and can be undone. But, it's becoming a bit of a PITA since she likes to buy apps and I like to stick to the free ones. Usually, when this happens her phone has not had any contact with my "home base" iMac which is where I do all my syncs. The only times she does connect her phone to it is only to charge it and not for syncing. Is there any reason for this before I go to the Genius Bar? Thanks in advance!