Perhaps they shouldn't be there, but their safety around tons of fast-moving metal is the only important thing at that point.
https://www.gov.uk/guidance/the-highway-code/using-the-road-...
"Watch out for pedestrians crossing a road into which you are turning. If they have started to cross they have priority, so give way"
There are distinctions to be made, when it comes to 'Right(s) of way' but your bizarre and daredevil interpretation of what constitutes a legal route for pedestrians and the call to ignore common-sense road security, would only be considered by those who have a death wish.
https://en.wikipedia.org/wiki/Right_of_way
https://en.wikipedia.org/wiki/Right-of-way_(transportation)
https://en.wikipedia.org/wiki/Rights_of_way_in_England_and_W...
Countryside. https://en.wikipedia.org/wiki/Countryside_and_Rights_of_Way_...
Your open-ended statement implies that legging it across a road is fine, as long as it isn't a motorway. This is not a safe guidance for the uninitiated.
It reflects the reality that, while cars should get out of the way of pedestrians, a car can't stop as easily as a human, so you can put yourself in danger by darting out into a street
The word "jay" is old American slang for "idiot", and the term was promoted by the car companies to push the blame for accidents onto pedestrians.