Pretty simple really; no bottom hammer on barrel boards, no rejumping barrels, no leeching kong on rivets, no leeching fire on elevators.
So, all 3 prizes are fair game on non-barrel boards?
How about incidental pie, spring, or fireball leeching?
Also, barrels must occasionally be re-jumped in defensive situations (e.g., climbing down a ladder to evade an aggressive fireball). Is that an automatic DQ?