lovely I am not 'entitled' or a twat, thanks. I am just pointing out that parents of schoolchildren are bound to abide by the exactly same road rules as anyone else. Illegal parking and driving without due care and attention is not allowed. Legal parking and safe driving is. It really is that simple. I do not park illegally or dangerously (usually the same thing) and I do not advocate anyone else doing it. Whether perfectly legal and safe 'pulling over' or actual parking constitutes unreasonableness is a matter of opinion. But for the people who do it, it's usually a matter of perceived necessity.
I don't see why children and the parents of children should be treated as second class citizens when it comes to where they can and can't park (legalities aside) and whether or not they should walk. Lots of adults don't walk or cycle or take public transport to work when they could - I don't see the same vitriol directed at them. 
JUST LIKE EVERYONE ELSE parents on the school run want to get as close to their destination as they can, as quickly as they can. Many parents are dropping off on the way to work so walking or taking the bus to school and then walking or taking the bus back again to collect the car or swapping to a different bus route is just not a practical or even possible option. Plus unless you are given free travel, buses are prohibitively expensive for a whole family when compared to the cost of driving.
If it is safe and convenient and the weather is ok and there is time to walk then I would almost always choose walk, and have done many many times over the years when I've lived within reasonable walking distance of school.
And when the weather has been fine I have often chosen to park in a further residential street rather than a nearer more crowded one. But that was when I lived a lesser distance from school and had the rest of the day to myself and nowhere pressing to be. Not everyone has that luxury. Once we moved to a school with a much, much longer commute there was no way I wanted to walk 15 mins from the the car and 15 mins back again after having just driven for 40 mins to get there and now facing a 40 minute drive back home - who would? Is my time less important than yours or anyone else's? 
Take school out of the equation a minute and imagine that's you going to work, or to the shops or an appointment somewhere. Would you do it, when there is free, legal parking much closer ? Of course you wouldn't.
But I don't see what difference it makes whether I am going to work or to the shops or taking my children to school. I am entitled to park legally anywhere I like and I am entitled to pull over to set down/pick up anywhere that it's legal to do so.
The councils know that to extend parking restrictions even further out just pushes the problem to a different street somewhere else. And after a while, those people will start complaining. PEOPLE STILL NEED TO PARK. WE ALL NEED TO PARK SOMEWHERE. And what happens if you get there and there, prepared to do your 10-15 min walk and there is nowhere to park because everyone else is doing the same thing, and you are going to be late for school?
If the restricted area is widened way too far, meaning that parents might face a 10-15 min walk from their parking spot to school and then back again (adding half an hour to their journey when they might be on their way to work) then that is not going to encourage them to park further away from school, it's just going to encourage them to get as close to the school as they can, and hover over someone's drive, or park illegally and risk a ticket, because you might as well be hung for a sheep as a lamb.
Because they have no choice. You can keep moving the goalposts all you like but it is NEVER going to make the problem go away.
When I was kid we all went to the nearest school which was almost always within walking distance. And if it was rural then the bus was free. And very few of our mothers worked so they had the time to walk with us if we were too young to walk alone.
Life is not like that now. We are encouraged to apply for schools all over the place, siblings get separated meaning more pressure to get to two places in a short space of time, fewer families have a SAHP, there's the pressure to get to work on time - that's just how it is. No point in getting all huffy about it. Just accept that for many families walking is out of the question.