In my experience, this just is not quite how the HSE enforce legislation.
From experience of growing up in businesses what they are looking for is the sort of person who fits the "Waiting for it to happen" catagory (like the pic of over stretching we saw earlier this week) and at the same time concentrate on improving those that are already doing something.
So for instance, a HSE does spot checks and spots a window cleaner. He goes up to him and checks first that the ladder is in good order. I am sure we all know long standing window cleaners that have nightmare ladders. Then they will look to see if any fall prevention equipment is being used, such as a M8rix and mitts which does seem to prevent the ladder moving. They then will check that you have injury prevention equipment such as a hard hat.
This obviously is not the exact way they will work, but it is the sort of thing they do. Depending on how many of these things you fail on is what splits the "stop working now" orders from the "I will be back in a month or so to see that you have done what I say".
I should think they will want to keep driving the figure down. It is all about statistics. If window cleaners keep falling off ladders and injuring themselves no matter what then eventually ladders will be phased out by the cleaners from being used for cleaning windows. I don't think that will happen for a long time though, the HSE will want to show how it has been able to enforce a policy and reduced deaths and injury year on year.
In the long run, with reductions in WFP prices and a greater emphasis on personal protection equipment for those who do work on ladders, it will become unviable to use a ladder, espcially if just starting out. The cost of safey equipment will be more than the cost of WFP. Basically it will be the big boys that can afford to use a squeegy at height and the rest of us will be using a pole.