First let me say, I know all about prison life because I've watched the entire run of HBO's Oz. Twice. Hell yeah.
Even if you don't have the kind of street cred that I do, you've probably seen someone with a tear tattoo. It's pretty common knowledge in the US that the tear is a memorial to a deceased loveone, but is also a prison tattoo that signifies the inkee has murdered someone.
However, in Australian prisons, tear tattoos are forced onto the faces of convicted child molesters. So, my advice to anyone who has a tear tattoo and has designs on visiting Australia: keep a low profile. Or invest in a tube of concealer. In fact, you might want to stay on the safe side and just make alternate travel plans.