Yes it is possible that a swan's wing could break a person's leg, arm or even ribs. If hit in the face, the wing could break a nose. We have been hit many times by even larger swans than the Mute species. Yes, it hurts, there are bruises, but luckily no fractures. So, even though it is possible, the wing would have to hit a limb the (wrong way) or (just the right way)---whichever way you want to look at the issue.

The other part of the equation would be the size and age of the individual struck by the wing. Yes, a very tall muscular person could sustain a fracture if struck the wrong way, but the probability would be less than the possibility of having a small child or frail person sustain a fracture. The Regal Swan