It's a negative trait for a reason. Deaf removes sound from the game entirely. By taking the trait, you're taking those risks. It wouldn't make sense to have a toggle because it'd negate the entire point of the trait
(Admittedly, when I first started playing PZ nearly 5 years ago, I always took deaf because I thought it gave me free points with no repercussions. I never knew that the game had sounds in the first place until I decided not to take it.)