What's the PG rule you most often forget?

[plloyd1010]

Our issue was that the 4th Edition rules specifically made assault a fire action so as to exclude transport unloading before assault combat. The 3rd Edition implicitly, and confirmed by consensus, allowed it. Because even the U.S. practicing 'assault unloading', and a good part of the existence of APC was to allow closing with the enemy, we decided to ignore the rule. We do technically require move of fire declarations, but since it is often obvious, we gloss over it most turns.