Most incidents happen while a rule is being broken by someone who knows it. The unsafe way is usually faster, easier or simply expected, and its benefit is immediate while the injury is uncertain, which is why rules and posters alone do not change behaviour.
Behaviour based safety works on that directly: a short list of defined behaviours, observation by trained peers, and immediate feedback without blame. When the same at-risk behaviour keeps appearing, it points to a problem in the system rather than in the people, and fixing that is where the programme delivers.