look here photo of lady on lake with pram She is pushing her pram on a frozen lake, nobody actually knows how thick the ice is, "it's thought to be 6 inches thick".
Ice doesn't freeze in an even formation, she hits a thin spot she or the pram containing small child is going in.
BBC news had a vid feed of a child playing on a frozen lake lake last night as well, at the end of the news programme thet'd obviously had complaints because they announced we shouldn't worry about the child, the "pond" was a very shallow puddle....
Don't walk on frozen ponds/lakes, it's not bloody well safe you idiots.