Except is construct actually on the stack if sacrificing the artifact is simply a cost of using proliferate, and you have to pay a cost of an ability before you can use an ability?
Okay, so can you then come with pre-made notes with card names? And then if so, can you alter them across matches or would you then have to discard them after modifying them during a match?
At the beginning of a match, each player’s note sheet must be empty and must remain visible throughout
the match. Players do not have to explain or reveal notes to other players.
Those two sentences contradict each other so now I don't know if anything you said applies.
If a player runs a card like pithing needle during a game in a tournament, are they allowed to in any way write down a card another player has in their deck so they remember it?
I'm not sure how multiple abilities trigger or resolve for Hardened Scales. If there are 2 out, then does a creature that would get 1 counter get only 1 extra counter, or, 2 extra counters, or, 3 or 4 extra counters?
If Reflector Mage returns a creature to an opponent's hand, but then dies, does the condition of not being able to be cast die along with it as it would with Meddling Mage?
Suppose a player declares attackers, then the opposing player sacrifices hangarback walker after attackers are declared. Does the opposing player get to put their ability on the stack before the original player finishes their attack in order to create blockers? Because entering combat and declaring attackers isn't itself an ability or spell, so it is unclear if it goes on the stack.
If a creature like Reflector Mage enters the battlefield, naming Walking Ballista, can walking ballista respond by blowing up reflector mage before that triggered ability resolves since ballista's ability would go later on the stack?
EDIT: Probably not since there is a rule that states an ability on the stack still resolves independent of the source's existence.
Those two sentences contradict each other so now I don't know if anything you said applies.
EDIT: Probably not since there is a rule that states an ability on the stack still resolves independent of the source's existence.