Seattle has made it official: It is now the first major U.S. city to ban plastic drinking straws.

As it turns out, the law, which includes a fine of $250 for all violators, is based largely on the unofficial research of a nine-year-old boy.

Probably not the best basis for sound legislation, but what do I know?

The ban, which went into effect Sunday, is an “environmentally friendly move that leaders hope will spark a nationwide conversation about small, everyday changes that people can make to protect the planet." Or so says the Washington Post.

The paper adds: “Now customers at grocery stores, restaurants, food trucks, even institutional cafeterias have to find another way to get liquid into their mouths. Compostable paper and plastic straws are allowed under the ban.”

The Post notes that the ban carries with it a $250 fine, but stresses that the law is not so much about punitive measures as it’s about “raising awareness.”

But this celebratory recap aside, here are a few points to consider. First, there’s the question of just how many straws are being thrown out every day in the U.S. The simple answer is: No one actually has a solid number on that, despite that anti-straw advocates frequently say it’s 500 million per day, implying that every man, woman and child in the U.S. drinks on average more than one drink with a straw per day.

The Strawless Ocean campaign, which helped lead the charge to ban straws in Seattle, claims “ we use over 500 million every day in America.” This advocacy group’s website links this figure back to a separate group called Eco-Cycle, which also claims, “ 500 million straws are used in the US every day.” And you better believe the 500 million number has been repeated by newsrooms. It has appeared in reports by NBC News, Reuters, Time magazine, National Geographic, the Guardian, the San Francisco Chronicle and the Los Angeles Times. Even the Post’s coverage of the Seattle straw ban included the figure 500 million.

This is where the story gets wild. Eco-Cycle told Reason magazine in January that it doesn’t actually have hard data to back this number. It has instead been relying on “the research of one Milo Cress....Cress — whose Be Straw Free Campaign is hosted on Eco-Cycle's website — tells Reason that he arrived at the 500 million straws a day figure from phone surveys he conducted of straw manufacturers in 2011, when he was just 9 years old,” Reason reported.

Put more plainly: No one seems to have a good number on how many straws are wasted every year in the U.S., but we’re passing legislation on the issue anyway.

This brings us to the second point, which is the problem of whether straw bans are even effective.

They are not, according to Reason’s Christian Britschgi. “The U.S. is responsible for a tiny portion of the world's marine plastic waste ( less than 1 percent), as are plastic straws themselves ( about .03 percent). The best approach to the problem of oceanic plastic pollution is better waste management systems in the developing world, not bans on plastic products,” he writes.

Yes, that would make more sense. But would that raise awareness?