Yup, that was day one. However, apparently we're pretty far from day one, and the magecrafters have made several innovations to this type of item. In fact, while it "may" be dangerous to do certain things (there are certainly rumors, stories, and legends (knowledge: Local) about it), in reality the only bug they haven't managed to hammer out by now is the portable hole and bag of holding. The interaction between those is still unstable. Of course, now you have to wonder how old is that haversack you're holding... and do you feel lucky, punk?