OK ewh,
You've got me there. It is never truely unavoidable. I will say this though. I have found that while trying to stick to the rules explicitly, I often end up with a more confusing drawing.
Here is my example, where I will try to explane with words, since I don't want to take the time to draw it out....
I have a box that I install in an aircraft. The box is screwed into a clip from the inside. Firstly I have to point to the box to call it out in the installation. Then I take a section of the box to show the fasteners, how the holes are drilled and whatnot. I also would like to show how the fasteners stack up because there exists a shim, and it isn't immedatly apparant where it is placed in the installation of the box. I have two choices, I can go back to the original view and take another section 90 deg to the previous section, or I can take a section of a section.
I find that, in dealing with the fabricators doing the work, that there is often less confustion about what the drawing is attempting to achieve by showing a section of a section.
I guess the point is, if you are consistent, and conservative in your uses of "breaking the rules," and you do it specifically to address some a particular problem, then you'll probablly be ok. If you do willy nilly, whatever you want, you're just a some hack who should probablly go back to middle school and get some drafting instruction from someone who'll hand you a pencil, not a computer mouse.
Wes C.
------------------------------
No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.