comparison

The strongest argument for using this method, rather than the traditional

- generate an element
- check if it was previously generated
- add to the selected elements if not previously chosen
- repeat until done

is that this method closer simulated the 'real world' application of

- pick an element at random from a pool of elements
- remove it from the pool
- repeat until done

The traditional method works just as well, of course, but only simulates the application, while the 'remove it from the pool' method is just more human-logical, rather than computer-logical.

In the end, when revising an old program, it's so much easier to figure out exactly what is going on, when it's doing something that's oriented to human-thinking, rather than computer-oriented conception.