My son was a runner - as in dangerously so (ADHD) and on reins, sometimes a little longer than usual, maybe a bout 50 cm, since I am tall. The abuse I got because of the reins and people tripping over them.
Often enough on a mobile phone.
Yes children should not block exits and entrances, nor be completely free range and potentially underfoot in a cafe or restaurant, or close to a road, or busy shop (espec. if there is a potential for the child to get lost or separated from the carers) but equally adults should stop and step out of the throng if they are using mobile phones.
Anyone pulling a trunk, or a case, or a beautician's equipment behind them should be equally expected not to prove a hazard to others.... and aware that other may have limited peripheral vision; I have to say in this regard adults have been the worse in my experience.
My great gripe is about ninja joggers/cyclists, in dark clothes and without lights or headtorch, esp on a poorly lit boardwalk. Also dogs that are not given a reflective collar or some such: I am walking in a reflective outdoor jacket, with a headtorch, and with my dogs wearing light-up collars (on a dog walking, beach unleashed permitted/welcome): do not scream at me if you run into my dog, or my dog gets antsy and a little protective if you come shooting out on foot or wheels at 8-10 miles an hour along a pedestrian boardwalk like a pounching camouflaged black panther...
WE were visible/