Display MoreI am sure it's similar in the US
If your dog bites someone, that is the issue regardless of a sign. If they are trespassing on your property, that might be a valid defence.
Does a Beware of Dog sign protect you in Canada?
Can a “Beware of Dog” Sign Prevent Me from Suing a Dog's Owner? A warning sign does not necessarily prevent you from suing the dog's owner if it attacked you. You may still be able to seek compensation for your injuries. However, you may also be partially responsible for the accident because you disregarded the sign.
Just to be clear, I am 100% sure that my dogs were behind my fence barking at someone else walking their dogs and stopping to pee on my light pole (the dog pee-ing, not the person, although I can't be sure). I just happen to have a street light pole at the front of my driveway in my grass and everyone stops there. Even when I let my dogs out, that's the 1st place they run to answer pee-mail and then come right back in.