A rule is generally something that shouldn't be broken, no matter what the situation is. Consequences usually follow right after a rule is broken. An example of a rule would be "No bullying". We all know that bullying can obviously lead to serious consequences when someone does happen to bully other people.
An enforced guideline is basically a guideline that has minor consequences. A guideline would be like when your teacher asks you to put capitals at the start of your sentence. An enforced guideline would be if your teacher hates when people don't put guidelines and has to pull you over to have a small chat.
