I'm no programmer, but the maximum viable value as a placeholder for non-viable or unknown values seems dumb. Even if the odds of the maximum value actually being valid and accurate are slim to none, it would be silly to introduce that risk willingly. It would make more sense and be more robust if it simply defaulted no "null" in cases of non-valid or unknown values. The 999... value is too big to make sense, and the placeholder explanation is too dumb to make sense also.
Since this Hal Turner person doesn't provide any source whatsoever I won't bother thinking more about it, frankly. Time will tell regardless.