Each opponent will know the decisions of previous opponents in turn order when making their decision
Its easy to trigger on your turn, especially if you play 0-mana spells and artifacts, and it doesnt take too much to sneak an extra card into your hand on another players turn
I thought it would be easy, like it was 20 years ago when every store sold them
However, these mechanic has specific rules and requirements players must follow
It is therefore desirable that each proxy is labeled with the name of the card it substitutes, and its basic game-relevant characteristics, and erase all decorations and printed information that may be misleading
Open the Vaults sounds like it was made for this Fallout MTG set, and it's a fitting inclusion in this deck