AIBU to think schools should not threaten parents with not allowing vehicular access to the school and with clamping if this doesn't work?

[TattyDevine]

They have some double yellow lines for the school bus. I wholeheartedly agree that people shouldn't park on them, as the school bus does need to park somewhere. But people do occasionally. There is no signage saying don't park there. The school do not yet own the land (its a Public Private Partnership type arrangement).

They have threatened parents who park on them that they will have a note left on their windscreen and a 2nd offence means they will not be allowed to drive into the school. Who on earth would enforce this? Would the police even be interested?

In addition to this, the headteacher ended the note by saying "if this more draconian approach does not work, we may take up the offer from a parent to introduce clamping". I thought since October 2012 clamping on private property was considered unlawful?

Or am I wrong about that?

The head teacher also asks parents not to park on the grass verge opposite the school (which is the highways agency responsibility and nothing to do with the school and not private property) because it leads to complaints from the parish council and local residents. But they don't own this land, and it is not illegal to park there.

I find it slightly worrying that a head teacher would threaten parents with something unlawful, regardless of their bad behaviour, without checking the legal position first. What are your views on this? Do double yellow lines on private property even have any legal weight? (I'm pretty sure they don't without signage).

Just for the record, I never park on the double yellows, because its obvious the bus needs to park there, but I am still left dumbfounded by the bizarre rant.

AIBU?

And I should add that my dad is a blue badge holder and his guidelines are quite specific that he can indeed park for up to 3 hours on double yellow lines unless causing and obstruction or there are other restrictions.

You are missing the word "usually"
Quite deliberate use of the work in the official guidance

There is no absolute right, this is at the compete discretion of the police or parking enforcement officer

I cut and pasted exactly what I found on the website, no deletion of words at all, I just added the emphasis. The word "usually" was not present on what I saw.

I don't get this. There's a double yellow line; even if it doesn't have legal force, the message is surely clear? So don't park on it unless you have permission to do so (not sure about badge holders and double yellows). Children who are unable to walk from car to school should have appropriate badge, the rest can surely walk?