Gentlemen, I agree anchoring would be a good idea, but in lieu of that (in case you want to move it around a little bit), wouldn't an additional piece of lumber at the base prevent tipping? I'm thinking a ~4 inch projection across the front of the existing base would be sufficient. Since you probably won't be placing other furniture immediately in front of such a rack, I don't think it would interfere with other furniture (tables, chairs, etc)