AIBU to say react when my DH does something wrong

[MoanCraft]

I just wonder what is the right way to react.
Here's the scenario: DH, DS and I pop to shops. We have lack of time so DH stays (happily) in the car while we pop out to 2 shops to get a necessary item for return to school.
We're gone about 10-15 mins.
Get back to car, no DH, car unlocked, my bag visible.
We get in the car DS says "where's daddy", I tell him he probably went for a wee. After 15 mins still no DH, I calm he says I'm coming to car now.
When he returns to car he realises we're in it and obvs he left it unlocked. When he gets in I'm annoyed as he left the car for quite a while, unlocked, as well as that he knew we were trying to fit loads in and in a hurry and he doesn't have the courtesy to let me know he's popped into a few shops himself.
So how would you react?

Sauce for the goose is sauce for the gander? What would he do if you 'disappeared' whilst out together?

My DH used to be really bad about this. I'm talking 25+ years ago before texts, cellphones, etc. I'd come home and he'd be gone without a note. So I just started turning right around and leaving again myself. Even went to the movies a few times. He got the message eventually.

No I wouldn't let that go.
I would tell him in no uncertain terms that we had been waiting for 15mins and ask him where he was. I would also point out that anyone could ahve stole my handbag and the car.

If that happened regularly, I wouldn't wait for him anymore, I would just go away and tell him 'Well I thought you were busy doin your own things and weren't interested in doing X with me'.

I don't understand this thing about saying nothing in front of the dcs. Surerly, it's good for the dcs to know that adutlts can disagree, can make mistakes and to show them a (hopefully) good way to deal with it?And perhaps even more if yoou have a dd, to show her that she can stand up for herself and not swallow everything wo a word?

Did he assume that you had taken your bag with you to the shop (as people normally would)?

Doing this on a regular basis is passive aggressive. He's messing up your day with his 'thoughtlessness' except to me it sounds a bit more like a general contempt of you. As I said a passive aggressive way of putting you in your place.

As he had form for this I'd have driven off without him. Who does he think he is? Don't just wait there obediently the next time while he deliberately inconveniences you and his own dc.

My DP used to just wander out of the house to visit neighbours without telling me where he was and what he was doing.

I just told him straight it was not acceptable. When we went to stay with his family, his Mum and Dad, brother and sister in law, nephew-all in the same house, with another brother visiting enough that he contributed to the food budget-I pointed out that they always said when they were going anywhere- 'I'm just walking the dog' 'I'm off to the shop, anyone want any anything' 'I'm taking the kids to the park'. I told him that is normal behaviour, behaviour that he had clearly been brought up with!

It was just what I expected from him and he started doing it.