No, I think the small openings are clearly person sized and meant for pedestrians while the larger chained openings are for cars/lawnmower/cleanup crew to pass through.  I do have some questions about the stated gap 20inch ~ 50cm seems small for strollers and wheelchairs so size is probably wrongly estimated. EDIT on reviewing the picture again the gap is indeed too small for strollers/wheelchairs. On an other note that chain looks too high for someone heavy to step over, she probably left or rolled under. I'm not buying that she stepped over it.