I too don't want to carp, but slowing down to 15 on a MUP around other traffic is not really slowing down. The first thing to expect on a multi use trail is that those using it don't know the "rules" and that many aren't familiar with "cyclists". They are simply "people" getting out, and in this case a child just riding along. Are they at fault, yes.................and no. I have a thought that had the child been injured in the 15mph crash that your boyfriend would have been fending off a lawsuit.