Medicare open enrollment begins on Wednesday. To kick off the season, the New York Times reported over the weekend that federal officials have repeatedly criticized and fined Medicare Advantage health plans for violations, including improper rejection of claims for medical services and unjustified limits on coverage of prescription drugs.

Medicare Advantage plans are private health plans that consumers may choose instead of getting Medicare directly through the government. These plans are offered by private insurers like Horizon BCBS and Aetna, and typically provide the same benefits as Medicare Part B and D through a private network. Medicare Advantage plans may be attractive to seniors because they offer a different cost structure than traditional Medicare, and may save you money on things like prescription drugs.

However, these plans won’t save you money if insurers unfairly deny coverage for things they’re supposed to cover, as federal officials charge. It’s a message to seniors to be wary shoppers when selecting between original Medicare and a Medicare Advantage plan, and to all of us that sometimes the law is only as good as its enforcement.