Disclaimer, not brave enough for AIBU!
Friends of our have always struggled with their dd (2.5) in the car and keeping her happy/entertained.
A while ago the dh said they'd been having problems with keeping her strapped in. We had a quick chat about it and to be honest I thought nothing more about it.
A week later I was with my friend at the park and as she went to leave I saw her put her dd into the car seat and only fasten it across her lap. It's a proper 5 point car seat but she didn't bother with the shoulder straps.
I mentioned it and she brushed it off saying she was always escaping and nothing they could do so didn't bother anymore.

So, I'm afraid my judgey pants were beyond giving me a wedgie at this point but I was a bit
so didn't say anything else.
When we got home I sent her a link to a few products I'd seen like the houdini to prevent them escaping the straps and she said it was a good idea.
Saw her yesterday putting dd into seat again and still not using the shoulder straps. She was talking to me and her dd leaned forward out of her seat and opened the door so they don't even have the child locks on.
I am beyond shit at saying anything in these situations but I can't stop thinking about it. I'm more than prepared to be told I'm just being nosy and to let them get on with it but what would you do? Say something? Leave it?
Help!