Simple Rule of the day for the moment, I'm drafting a list for the next one about reforming. May hit the shelves later today still.
Before answering any rules questions, or 'knowing' the rules answer - Read the latest GW FAQ or wear your face-egg proudly!
I personally got recently 'bitten' by this where I made a devils advocate argument against a ruling. A quick read of the FAQ (mentioned by another person) immediately squashed my 'jukey' argument.
If you are playing in a tourney, have them on hand if you are going to argue that position.