Knowing magnesium burns as brightly as it does and is so difficult to put out once lit, having done both as a kid, I'd always just assumed magnesium was the name of the paint color or something - not what it was really made out of. As they'd mentioned briefly in the article, water just makes the flame worse rather than better.

Seems like asking for trouble, but perhaps it's enough of a pain to light initially that it's not a concern?