What is the preferred method of using `std::rel_ops` to add the full set of relational operators to a class?

[This](http://www.cplusplus.com/reference/std/utility/rel_ops/) documentation suggests a `using namespace std::rel_ops`, but this seems to be deeply flawed, as it would mean that including the header for the class implemented in this way would also add full relational operators to all other classes with a defined `operator<` and `operator==`, even if that was not desired. This has the potential to change the meaning of code in surprising ways.

As a side note - I have been using [Boost.Operators](http://www.boost.org/doc/libs/1_46_1/libs/utility/operators.htm) to do this, but I am still curious about the standard library.