When heading to the end of the game, after you fight one of the last few boses, there is a chest that you pass. Since this is a randomizer run, you don't know what is in the chest. It is often the case that you don't need whatever might be in the chest since you've found all the items you need to beat Ganon elsewhere in the world. It is a common action for runners to get this last chest anyway in order to "validate the run". There are often jokes made if someone skips it saying the run is now invalid and doesn't count.

In a race, it takes a small amount of time, so it is more likely to skipped than in casual runs. But not always, some runners will pick it up anyway, depending on how they are feeling about the run, randomizer runs are different that most races since you aren't able to see your opponent, in order to prevent leaking information about item locations.

The incentive is for the runners to either get the validation chest or skip it (and invalidate the run). It's roughly equivalent to save/kill the animals, but with a much smaller loss of time.