Name changer as I don't want this linked to my normal name.
Saw the DH of an old acquaintance, never liked him, misogynist prat.
He had his young son in the cart with him when he pulled up in the car park.
Front of car, no seat belt. 
Coincidentally we left the place at the same time, drove off, child in front, no seat belt. Actually was sitting with back againt the dashboard, backwards, iykwim?
I nodded at the DP in the venue, but due to my non confrontational issues, I said nothing.
AIBU to be ashamed to think personal fears perhaps overrode this child's safety? Tbh Ithink even if I had said anything it wouldn't have made the arrogant idiot secure the child.