A Leg Up
Did you ever think about how people with only one leg can't trip on their own untied shoe lace. Or how hopping gives you a height advantage allowing one legged people to see enemies coming from further away, and maybe just maybe that compensates and perhaps even over compensates for the slowness of hopping to safety. In that same regard how hopping children are more visible when crossing the street and therefore less likely to get run over. Or how hopping is better cardio than walking. Having one leg vastly improves your survivability in today's urban environment, and thus I suspect that these one legged people are not the result of accident but rather that of evolution. Well the ones that were in accidents are obviously the result of accident, but the other ones; you know which ones I'm talking about, are a glimpse at the future of the human race.
