There's no situation in the game where you are allowed to simply deny your opponent information that impacts the game. You could make a case that there is precedent that allows you to delay such information until it impacts the game, though, by citing enchantments.
You are not allowed to cover up or hide printed information. I do not have to tell you my mana total or current life score. You would have to get up and look for yourself.
If we are playing and you ask, "what enchant is revealed on that creature? " I do not have to tell you. It is your responsibility to look at the board and read the cards.
This topic has never been about denying information; It is about my responsibility (as a player) to interpret the pregame book construction rules for you.
Do I have to tell you that my Warlord is trained in War? No. Do I have to tell you what my wizard is trained in? No.
As for enchantments. If I slide a hidden bear strength under my zombie brute, that is an illegal play. However if I shift enchantment that bear strength to my necromancer and reveal it was an illegal spell cast?
Same situation but you cast a seeking dispel on that zombie brutes bear strength...
So you see there are some examples that go beyond the identical enchantment stacks argument for hidden enchantments.
As for examples of information you do not have to tell your opponent. I do not have to tell my opponent any prepared spell information, the number of spell book points my book is, if any illegal cards are in my book, my spawnpoints prepared spell, what any hidden enchantment is, and my wizard training
I can not hide any printed or revealed card on the table. You can not cover up and hide any marker, or card, on the board or mage status board.
You may not shuffle the order enchantments are placed, but I do not have to tell you what enchantments are placed in what order. It is your job to keep up with that information yourself.
Lets say its an official game setting. I ask to clarify your mages trainings… this could be for whatever reason, but there is currently a grey area/undefined aspect on the board that Id like more info on or am uncomfortable with. Then you say no.
Unsatisfied, I then have an official come over to clarify the variable. I don't see any reason that said neutral party would have any basis to say "Thats his secret, you have to just guess." rather than to clarify the state of the game. To me I just don't see any grounds for it to be secret other than a player trying to be shifty.
I'm sorry, but, I think you need valid reasons to have a judge stop a timed game to satisfy your none game-mechanic impacting, personal issue. If you called him over I assume he would count my wizards spellbook and tell you that it is a legal 120 point spell book. After that he can not tell you what cards are in it or if it favors one school or the other.
When such elemental only spells are introduced into the game they will be handled like any other restricted spell in the game. When my water wizard casts a water only equipment or spell it will resolve accordingly. If I later cast a fire mage only spell then a flag goes up and you say,"I think we have an issue." Just like with any other mage in the game right now.
Mage Wars assumes you are making legal plays until an illegal play is made, and handled accordingly for all instances. It never once makes you prove that you are legal target for a spell, it either is or is not. If you attempt to cast a spell on an illegal target it fails either before or after the counter spell step (as described in the FAQ) and plays out as per the existing rules.
If you try to cast a sleep on my zombie, it is not my responsibility to say, "Do not pay the mana for that my zombie is immune!" In mage wars information gathering is the responsibility of each player, not the responsibility of the player to give that information and assist you in casting / preparing spells.