First point - clearly this man doesn't understand the symbolism of the number 666. In Hebrew, words correspond to numbers based on what the letters add up to, i.e. the word for "life," which I think would be transcribed in Roman characters as "chay" (pronounced "hi" with a bit more phlegm on the "h") adds up to 18. As such, when Jewish grandparents send their grandkids birthday checks, multiples of 18 are common.(Aside: Someone tried this numerology to prove that the internet was Satanic by pointing out that the Hebrew character equivalent to "W" was 6, and as such, "WWW" translated to "666"...but clearly there is a lack of understanding of how Hebrew numerology works. The numbers are added together, not read sequentially; as such, "WWW" would actually be 6+6+6, or 18 - the aforementioned "chay," or life. As such, the point being "proved" becomes an epic fail."
In any case, the number 666 was used in a similar manner, referring to an actual person - Emperor Nero, who, judging by the way he was discussed by Roman tour guides when I was in Italy last May, is the Roman Empire's equivalent of Hitler in how he's perceived. It would be the equivalent of people adding, say, a modern liberal political commentator's writings from the mid-2000s into a holy book in a couple hundred years in which former president George W. Bush is referred throughout as "W," stating that "W is the greatest enemy to human civilization," and people in the year 4000 being squeamish about the letter W being in anything.
Second point - skipping unlucky numbers is appropriate in some places, i.e. the 13th floor here, the 4th floor in China or Japan, the 4th spot at a baccarat table, etc. For an employee ID? Don't be stupid, stupid.