Yeah I'm very confused too. Apparently some copies don't have the moving dot effect, and others do? Does that mean there are sources without it? If that's the case, I'm very curious as to what source doesn't have it.
Does Amazon, or iTunes, and Hulu, and Nickelodeon (the channel), and Nick.com have this problem?
EDIT: I wonder this because I don't want to watch SpongeBob with the distracting VHS effect, knowing there are better and cleaner looking copies (Copies that don't have SpongeBob as pale yellow in S2).