control. They are naive to think they can train the dog not to bite again. It will likely get put down.
You can decide whether to just let them pay medical bills. If the wounds are serious - this would have been a $250K lawsuit in average in 2000 in Orange County according to an attorney friend of mine back then.
If they are homeowners, they will have liability coverage that will pay out any damages.
You could discuss this for free consultation with a personal injury attorney or your insurance agent. Or, you can be really generous and just let it go regarding damages.
Regardless, you have a duty to protect yourself and others from recurrence. Report it.