You mean like with this guy. MoM?
These pics are from 1979, and initially I thought his jeans were a slightly flared boot cut. Then again, they're probably just hanging that way.
Also, there's the 'flare effect' due to pressing/ironing when you get your jeans back from the alteration service with fresh turn-ups sewn in. I need to soak the hems in cold water every time just to get rid of the flare...
But I think the kid's jeans in the original photo actually are bell bottoms.