To think this women is irritating

[sophisticatedsarcasm]

There’s this one Mum at the school, she’s always been annoying. She asks random people to be friends with her 11 year old daughter, she lets her youngest son (3) ram people on his little ride on. She doesn’t stop him or move him along just waits for him to go at his own speed. Everyone gets annoyed with her. She just smiles .
So today we have a meeting about the new way to teach kids to read about phonics. 5 minutes in she comes in slams the door open, then her boy comes in on his really noisy ride along so we couldn’t hear a thing, after 5 minutes they finally stop making noise, only to hear him a further 5 minutes later leaving to go to the toilet. AIBU thinking she shouldn’t have let him bring it into the school (she drives so could have left it in the car) she disrupted the meeting, didn’t apologise and was completely blasé about it knowing full well everyone including the teachers were visibly pissed off.
My mum then tells me she goes to my mums work and they’ve had to warn her about the ride on as her son has knocked several things down,

I know a mum like that. She’s exhausting as are her kids . Sympathies.

Didn't you say anything to her?

Why a biscuit

That type of twat mum sounds very familiar.

YANBU.
When it’s a school event could you speak to teacher, explain that you couldn’t hear and ask that ride on / noisy toys are not brought to future class meetings?

If outside school, tell the DM / DC he’s hurt you and firmly ask him to stop ramming you.

Not sure why everyone is indulging this antisocial behaviour.

Oh he hasn’t rammed me with the ride on, just witnessed him doing it to others. I didn’t say anything because I’m not the sort of person to start drama. I keep myself to myself a majority of the time. On many occasions she’s lost him in the playground. She’s asked me before if I’d seen him, I’ve been tempted to say if you kept an eye on him it wouldn’t be a problem.

It isn't up to you to Police their behaviour. If others aren't dealing with it, when they are ramned then it's none of your business. Likewise who she asks to be friends with her DD.

The Teachers should have had a better control of the meeting.

It isn't that unusual to lose sight of a child and if you've seen the child you'd be a twat not to say so.

You don't like her and are being overly picky.

It was a phonics meeting not Cambridge admissions.

She might be a shit parent, an overwhelmed one or a winging it one. Not convinced either way.