As always with these things it depends on context.
When I see a place that is somewhat overprotective in “warning” about everything that could possibly happen to a person, then it becomes just so much noise, and especially so when the place is managed – usually well-managed – to mitigate most hazards, then it’s ignorable, probably redundant, and maybe even stupid. (For example, a business office with a “Watch Your Step!” because you’re walking through an exterior door that has a threshold. It’s like, “Really? You think I need a warning for a threshold? Have I never seen an exterior door before?”
On the other hand, some places are not so well-run and informative, like a messy, dimly-lit industrial building that might have an unexpected step up or step down to or from the shop floor, but the floor is dirty, there are no other floor markings to indicate the elevation change, and people unfamiliar to the environment can miss the change and trip, then those warnings are golden. And necessary.
Context. It’s all context.
EDIT to add: Sometimes, in contradistinction to @Seek‘s humorous example, the emphasis on safety is misplaced.