If you use a public computer at a school or net cafe, please please delete your data when you're done. Sign out of every webpage and IM client you logged in to. Make sure there are no footprints of yours left. Firefox has an option in the Tools menu to Clear Private Data, use it!
I work at an interent cafe, I find resumes, love letters, family / vacation / naughty pictures, contact lists, privately produced music, boarding passes and itiniraries, credit card numbers. Basically I find enough information to completely assume your identity and stalk your family. I'm a white hat for people. You're lucky if you leave your stuff and I find it, all I do is copy it to my vault and remove it from the public.
I guess people in Hawaii are more laid back about this kind of stuff, but all it takes is one person bent on chaos with enough smarts to realize what they've come across to make your life way more difficult.