People get used to their workplace, comfortable and complacent to the point where they don’t see the dangers in the machinery they work with routinely anymore. It’s the responsibility of the business owner to make sure they never forget.
Take reverse signals for example. They’re like house alarms. After a while they just become background noise and no one notices them anymore, never mind heeds them, even when a 30 tonne truck is what’s emitting said signal.