If you needed another warning to be careful what you’re posting on Facebook, there’s this: Seven hours after a 17-year-old Australian posted a picture of herself counting a large sum of money belonging to her grandmother, two armed robbers showed up at her house.

In their media release detailing the robbery, the New South Wales police closed with this statement: “The incident has prompted police to remind users of social media to take extreme caution when posting photographs and personal information.”

The problem, hopefully, isn’t your friends, though I wonder if the people who have 500 FB friends really know how trustworthy those “friends” are. Your friends’ friends are an even bigger concern. I have closer to 50, and have friends of friends who are pretty scary.

Making things worse, the default visibility for photos is public. But if your social circle contains (potentially) 500^2 people, the “friends” visibility may be too much–remember, when a friend comments on a photo, other friends see it.

When posting a photo, you have to think of the seediest bunch of cutthroats, villains and scoundrels you have ever seen. Then think of your friends. Some of them are Facebook friends with members of that seedy bunch, and potentially will see that picture.

So you should be careful what you post, because you have to assume that unsavory people will see it, whether you like it or not. Posting a photo of that obnoxious wallpaper that you eradicated from this world this weekend is no big deal, but if you find a cigar box of old gold coins in your attic, Facebook isn’t a good place to talk about it. Or worse yet, post photos of yourself counting it.