There are large parts of the South West Coast Path (and likely many other coast paths) where the going is somewhat hazardous and a fall could easily result in injury or death. I remember walking along a particularly high and narrow ledge south of Porthleven some years ago. Some of the descents between Bude and Hartland Quay, or between Lulworth and Worbarrow Bay, are extremely steep and rather nerve wracking - if you stumble, you could travel a long way. Removing risk altogether would basically involve closing the coast path. Probably not going to happen, although some sections regularly do get closed after cliff / rock falls where the risk is considered too high.
Not on the coast path, but adjacent to it is the Cobb in Lyme Regis. For those who don't know it, a slippery harbour wall sloping downwards to the sea with no shelter from south westerly gales. A tourist was injured when they slipped on some algae in 1988 and sued West Dorset DC in Staples v West Dorset. WDDC weren't found to be negligent, but ever since then there have been warning signs about the risk if going onto the Cobb.
At Charmouth, where I grew up, there are numerous signs about swimming in the river Char and about going too close to the crumbling cliff edges. Invariably, most summers someone gets into trouble and complains that no-one warned them. However it never seems to go further than grumbling to the Dorset Echo.
As others have said, there are plenty of measures between doing nothing and total closure. A few warning signs at appropriate locations are usually sufficient.
Here in York, every few years there is a tragic case of a young person drowning in the river and the families embarking on campaigns for more and more signs, barriers, lights etc. It can be very difficult for friends and family to accept, and it's not uncommon for them to feel a sense of duty to do something to try to prevent future incidents. But our judgement can be impaired when we are upset; that's just part of being human.
I would agree. I have no idea on the details of this specific case, but in general terms I suspect that it is very difficult for the bereaved accepting that a loved one's recklessness may have contributed to their death (and again I am not suggesting I have any idea what happened here, nor am I suggesting recklessness negates negligence by another party). Much easier to blame someone or something else for not preventing the death.
I can't recall where but I'm sure I have read on this forum that a key reason why inquests are held for suicides on the railway is that the deceased's family will often try to blame the driver for not stopping - easier to focus their grief on a total stranger. The inquest is important for highlighting that this is invariably impossible and no blame attaches to the driver.