Originally posted by Bob Narindra:
Let's use three scenarios to illustrate this:
In case 2, you don't have to investigate cheating, it IS cheating. The text clearly indicates the intent of Nate.
In case 3, the exact same physical actions happen, but the thought process in Nate's head is different. It's all well and good to debate the different reactions a judge should have to case 2 and case 3, but in an actual tournament environment, there is no difference. A judge simply has no tell to differentiate between the two.
The Comprehensive Rules give us a 100% robust solution to genuine errors of players trying to play spells without targets, or with improper mana. That has to take into account weird interactions with
Chromatic Sphere and
Future Sight. For tournament magic, we use different criteria.
If the opponent hasn't had time or ability to react to the misplay, we can rewind stating the player was ‘thinking outloud’(when naming a spell that is not shown) or ‘thinking physically’ (when tapping lands). If the other player had time and opportunity to respond, but has a good poker face and elected not to, the play stands.
For me, there are 3 options:
1 The player played the spell (announced it, choose targets or mode, didn't pay mana) and passed priority, and will recieve a GRV for playing the spell without tapping mana.
2 The player hasn't completely played the spell, and was still deciding what to do, but showed a hand card to the opponent.
3 The player is cheating by trying to force his opponent to reveal strategic information by making the game state ambiguous.
The line between 1 and 2 is determined by asking questions about how exactly stuff was tapped, how things were played earlier, and the board state (is the other player monored, tapped out and no handcards, or are there 5 untapped islands and a full hand of cards?) You need to determine whether the opponent had time & opportunity to show a reaction. That will define which option it is.
For option 3, you need to ask not just ‘how was stuff tapped’, but also things ‘why did you not do …’ (fill … in with some other option on the board (if in front of the opponent) or in hand (if you have the player seperated)) Also, consider this: A player is showing a card from his or her hand, solely to determine whether his opponent has a counterspell in hand. Obviously there will be situations where your hand information is not relevant, but your opponents is, but in general, this doesn't seem like a very optimal method of cheating to me. Especially considering the amount of players that get into this situation. So unless a player flatout admits to being on a fishing expedition, I don't think you should investigate these types of errors for very long.