For teams that have only three participants, why can’t they receive the ten extra bonus points if they answer all questions correctly?

The Bible Bowl Handbook states bonus points will be awarded when four participants answer all questions correctly. This is one of those situations that we have to draw the line. If we allowed a team of three to get the bonus, someone else would ask why not a team of two? It is more difficult to get all four answers correct than three, so the committee feels it would not be fair.