As long as it is there just to improve safety. But it should not be relied on.
In other words, if you 'hear' "don't go", you don't go. But if you don't hear anything, it still doesn't mean it's safe to go, so you'll have to rely on something else. And if you are doing that anyway, is the added complexity worth it?
In other words, if you 'hear' "don't go", you don't go. But if you don't hear anything, it still doesn't mean it's safe to go, so you'll have to rely on something else. And if you are doing that anyway, is the added complexity worth it?