I grew up around coyotes all my life and I can safely say that coyotes going into a fenced yard after children is not normal behavior. If they aren't rabid then they have become accostumed to the humans and were probably stealing cat and dog food, plus a few cats (coyotes favorite food).
I agree with coopcrazy, coyotes usually only will attack when cornered, they want to get away from humans. If coyotes attack a human they are usually sick (i.e. rabid) or there are way too many and they are starving. They may also have become used to humans and there is no hunting pressure...