Have you tried pushing a pram around London?
None of the pavements are level, the dropped kerbs are missing or blocked by illegal parking, the crossings are blocked by busses, and as a result its a genuinely physically exhausting activity.
On top of which, the parent is dealing with years of sleep deprivation, a badly behaved child, the generally shittiness of being a parent, the stress of being late for everything, a mountain of un-done work and personal admin, and the outright hostility of commuters.
Sometimes, under these circumstances, bad decisions are made. Best to give pram-pushers a wide berth whenever you can. Or at least have the decency to aim for the parent and put them out of their misery.