DISCUSSIONS on “Rules for online games in HoMM3 and formulas for calculating player rating.”

There is, by the way, an interesting point related to this rule. If you kill an enemy hero who has the Grail set up and dig it up with all spells, you can use them without restrictions, since it's impossible to clearly determine where they came from.

Why kill them... nowadays it's fashionable to hire and fire 5-10 heroes per turn, so having the Grail in a favorably located Conflux will lead to the fact that very soon many heroes with all the spells will be sitting in the depths of the tavern. And it may turn out that the player who placed the Grail is still building Cap5, while their opponent is already making full use of those scrubs :)