Beware of Dog sign?

I heard that if you have a "Beware of Dog" sign... you are "admitting" that you have an aggressive dog, so if your dog bites someone you will be in more trouble because you are admitting liability/saying that you know you have a dangerous dog....However ...I have also heard that if you have a "beware" sign you are actually protecting yourself from litigation if your dog bites someone because they were warned before entering your yard.....1st time dog owner..he is not an aggressive dog....and is only out in the back yard for about 2 hours in the morning and 2 hours in the evening. Thanks to you all ..