Or just leave your doors unlocked at your house and twitter that you are leaving for the weekend.
"Jail" "break" mean that you are "breaking" the BSD "jails" that protect your phone from third party apps running amok. You are effectively turning your security into swiss cheese.
While, potentially, it's indeed a security risk, an app indeed running amok still remains to be seen.
I've long been jailbreaking on several of my numerous iOS devices and have always been installing tons of Cydia stuff (even ones without dependable references / reviews). No problems / viruses / trojans encountered.