This mindset has been encouraged by the government - i.e. if people fall ill it is because someone has flouted the "rules", which isn't that difficult to do, given that they seem to change from one day to the next and there are so many inconsistencies. Also, even with the most conscientious people, it is not possible to eliminate risk completely.
Unless every single person locks him or herself up, away from everybody else, and never ventures anywhere, this virus will continue to be contracted by people and will affect them to a lesser or greater degree. However, when people exit a lockdown, presumably the virus is there waiting. I recall a medical person saying that viruses don't retain their power to cause serious illness or death but eventually weaken and then disappear. Perhaps that should be the best we can hope for.
I really don't see why the elderly lady who fell over shouldn't go for a walk without being branded selfish, passive aggressive, etc, etc. The gentleman's wife has taken it upon herself to be constantly at her mother's side (and I am surprised that this is allowed). To visit for an entire day is completely over the top.
Mynxie I appreciate that you, like many other people, are nervous of the current situation regarding your Mum and I understand you fear catching the virus from her. I can only suggest that you explain that for the time being you will limit contact to telephone calls as you are frightened of getting the virus. In such a way, you have made your decision and she is at liberty to decide whether she wishes to alter her behaviour or not. It is not as if you would be leaving her isolated and alone because, as you say, she has several friends.
I would agree with those who say you may well be at more risk from mixing with the rest of your family, especially your grandchildren. Children are said to have far fewer, if any, symptoms and if they pick up the virus it may well go unnoticed for several days, if at all.