Ive never had a problem with my child sitting in a pram either.. But theres only so much shopping one can carry/balance while pushing a pram.. Therefor my son either sits in the trolley seat or sits/stands in the trolley..
He doesnt jump around, go crazy, lean over the edge or anything so im not greatly concerned for his safety.. I believe he is safe..
Would be worse if he wasnt in the trolley and ran off and got hit by a car or something equally as tragic.. That wouldnt be pretty..