Hmm help

How do I go about telling my best friend that she doesn’t have her baby properly in her car seat.. the straps a very lose, chest clip is down on her belly because she has the strap protector things on them.. I don’t want to come off rude but I don’t like see a baby that way.. I tried to say the strap protectors are unsafe but she blew that off and said they wouldn’t make them if they are unsafe