Every day I pick up my DS at about the same time as another mum. She has a 3-4 yo and an 18-24 month old (don't know exactly but both mobile). Nursery pick up zone is on a workplace site which has a very low speed limit but not necessarily great visibility between the parking zone and the through route. It is the total lack of control she has, with her younger child in particular, freaks me out. She is not completely harassed or fighting with them, she buckles the older one in first and the younger runs about between the cars/on the pavement and she lets it be a game. A lot of the time she can't even see him.
I have often just sat and not started up my car until I can see that she's got hold of the younger one. The other day she even got into her driver seat, shut the door, looked out of her open window and said 'alright then, I'll go without you' while he stood around between cars (actually, in front of mine). He just stood there and smirked back at her, she got out and picked him up, and then got him a snack/drink or something out of the boot.
It's one thing to relax the rules in a safe place but I don't think that most toddlers really have much judgement about which are the safe places to muck about or not. I am not trying to be holier-than-thou but we make DS hold a hand in any car park or road, even if absolutely deserted.
The site management went to some lengths to design a safe parking zone and set the speed limit at 5mph - which is nearly impossible to do without stalling! - and I am sure that the nursery can't actually do anything once parents have walked out of the door with their children, but should I mention it in case they choose to have a word? I am feeling too chicken to say anything to the mum myself - only a nodding acquaintance. If I did, would something like this be ok: "could I suggest that you buckle in the younger one first, and let the older one demonstrate he's old enough to be able to wait carefully around all these cars?"