Fences on the bridges will help prevent people being pushed off them, too, Steve. Or heavy objects dropped onto cars below. Fencing the bridges is not just a deterrent to suicide but a vital public safety issue for a variety of reasons, not the least of which being removing the ability to quickly make a rash decision to simply throw a leg over and jump. A bystander might be able to pull someone back trying to scale the fence, too, and restrain them until law enforcement or other help can arrive. You're right that mental health treatment is at the core of the problem, but what if someone's illness isn't identified until they step over the rail?