Minnesota health officials are warning people about possible scammers as free testing sites begin limiting testing appointments because of scarcity and hoarding.  Vault Health officials say there is an unprecedented demand at its free state testing sites.  The Better Business Bureau chapter for Minnesota and North Dakota is joining an Illinois investigation into the Center for COVID Control which is operating testing sites in Minneapolis, St. Paul, and other locations in the state.  Delayed or inaccurate test results have been reported by some using the company’s site.