The problem we have at the moment is that the public have very quickly latched onto the new elements put int the most recent addition of the Highway Code and are using it to their advantage.
What the current HC now says is
There is now a hierarchy of road users who is most at risk in the event of a collision, starting with pedestrians at the top, followed by cyclists and it goes all the way down to HGV drivers at the bottom.
To this end, an additional requirement was included within the Highway Code that makes it a requirement for drivers to give way to pedestrians at junctions as well as at Zebra or other controlled crossings, which means that -if a pedestrian steps into the carriageway at a junction because they cannot be bothered to use the pelican or zebra crossing 20 yards away and a collision occurs resulting in injury, the car driver will be held liable.
But it is also being interpretated as "If a pedestrian crosses in any part of the road" the driver will be held liable, and the worry is that these people (schoolkids becoming some of the worst offenders) are using these new rule to make fake cash for crash claims and making easy money. (I should add its not just kids but a whole spectrum, but the kids loiter on street corners and are playing chicken knowing they can make easy money in the right conditions)
This new rule was added by a member of the Pedestrian society and there was no consultation on the inclusion> I know of a dozen personal injury cases where already settlement has had to be made because of this ruling which has been in for about 18 - 24 months.
So back to the original point made by the OP, I think now there is no such thing as being unreasonable. I take any pedestrian stepping out as a potential threat, and most/many of them are playing on this fact, other than the other reason namely they have their faces planted so deeply into their mobile devices they are not even on the planet, but that is another story.