Against allowing the installation of the Grail.
What negative consequences this could lead to.
I was just reviewing a controversial save game when the Player dug up the Grail after 3 attempts on 3 obelisks (there were no crosses, of course).
Of course, I allow for a certain percentage probability that the Player played fairly and didn't look for where the Grail was located, but I give an even greater percentage probability that the Player cheated. And by defending the rights of one Player (who dug up the Grail), we must also think about his opponent, who may have been left "in the lurch," because comparing the percentage probability of fair/unfair play in this case falls into the category of "grandmother said it twice" (i.e., very uncertain).