I can only imagine that "Nature's Miracle" contains something that, if you had thousands of gallons of it, you might use to make a bomb. I still wouldn't give out my BIRTHDATE to buy some, however!!!
Those who object to giving out their zip, may I ask why? (aside from the annoyance factor). I'm hyper-touchy about giving out personal info, but I don't mind giving out my zip because it isn't really connect-able to me, personally, and it is one of the more legitimate marketing tools.