Have you ever played a long game where two players are competing fiercely and a nasty rules argument gets going?
If you ever wonder why gamers can be so picky on rules, this is part of why. Ambiguous rules make for horrible arguments, and they will happen right when it really matters.
As a gamer, it is not fun to play a long game and get into a situation where two players both think they are right about a rule interpretation, each was counting on his interpretation, and it turns out that both interpretations are valid.
No one ends up happy. If you write rules, please make them as clear as possible.