You can lose ratings for things like not keeping fridge charts up to date, not recording accidents etc, the ratings cover a lot more than just cleanliness these days and encompass the whole business operation.
A good mantra that has helped us maintain standards is, say what you do, do what you say, prove it.
The current "safer food better business" manuals that are issued by the FSA have 10 chapters in them with documentation that needs regular updates, it is a bit like the BS/ISO quality assurance manuals used in industry to prove that you have control of the business.
Generally speaking chefs don't like paper work and can fall foul of keeping up with it. The responsibility though is with the owners, when the chef owns the business it can get neglected. Not many chef/owners can run a food business successfully these days as the paper work can be very time consuming.