I wouldnt walk into a "B" rated establishment.
Somehow this system managed to stigmatize anyone below an "A". These ratings are based on extremely strict regulations that are really really hard to follow for practical reasons. I've spoken to an owner of a prominent restaurant (who, BTW, has an A), and he told me that people have no idea what kind of vicious screening they have to go through to get (or keep) that A. So to say that you wouldn't walk into an establishment with a B is like saying you wouldn't walk into your own home kitchen (which probably barely makes a C), if you're familiar with the regulations. This system is pretty good for the customers, but is a literal killer for small businesses.