36 states and DC have strict liability for dog bites. For most the only exceptions are if the person was trespassing when they were bitten, if they were provoking the dog, or it's a police/military dog doing its job. Some of those states have carve outs where they only have liability for expenses if they didn't know the dog was dangerous (I'm presuming that means no emotional/punitive damages).
Doesn't matter what precautions the person took, if the dog gets out and bites another person, they're liable in most states.