The coding standards are the least of your worries!

Surely. These are guidelines. And my list is not complete I might add. I like to formulate them a bit strict. Firstly to make them clear. Secondly to steer programmers with little OO experience away from the abuse their instinct seems to drives them to. You are allowed to break the rules when you understand them a kind of being the motto.

There will always be situations where we have to break the rules. Rules cannot deal 100% with all the details a quirks of reality.

And, of course, there are always situations where the nature of the underlying problem is such that deviation from the rules is the required solution, such as building a class hierarchy, or using friends.