为什么每个人都使用unanchored名称空间声明（即std :: not :: std：:)？

It seems to me that using unanchored namespaces is just asking for trouble later when someone puts in a new namespace that happens to have the same name as a root level namespace and mysteriously alters the meaning of a whole lot of programs. So, why do people always say It seems to me that using unanchored namespaces