Whether or not you're behind on your utility bills, don't square up with the person who knocks on your door without knowing first if they're legitimate. The Better Business Bureau is warning that thieves have been going door-to-door in and around Brooklyn Park recently demanding that residents pay their past-due utility bills on the spot using reloadable debit cards, such as Green Dot MoneyPak cards available at many retailers. "This is a particularly bold scam," said Dana Badgerow, president and CEO of the BBB of Minnesota and North Dakota. The scam, also run by phone, has shown up in other parts of the country. Utility companies usually send payment requests through the mail, but in rare instances, when other collection methods have failed, a utility company representative may show up in person. "Even then, they will have proper identification and welcome you to call the utility company to verify their identity," according to BBB spokesman Dan Hendrickson. Be leery if a person at your door demands payment by debit card. Once criminals have your debit card information, they can drain the card of funds, the BBB said.