Cactus Game Design Message Boards

Angel from the Altar:
You may banish up to X evil cards from a discard pile or you may exchange a good card from hand with a good card from Reserve. Cannot be negated if The Golden Altar is in play.

Noah:
You may exchange a card in hand or territory with a human of matching brigade (or 2 flood survivors) in deck or discard pile. May band to a flood survivor. Cannot be interrupted.

All abilities that target hand have an implied reveal ability, where if the holder of the targeted hand cannot complete an action required by another ability or game rule, they must reveal that hand.  For example, if a card requires a player to underdeck two good cards from hand, they must reveal their hand if they can underdeck zero or only one.  If they can underdeck both and satisfy the requirement, there is no reveal.

If a search ability targets a specific type of card, reveal the targeted card before performing any other action with that card.

Do you have to reveal the card you exchange from hand with Angel from the Altar or Noah?  The REG entry on Reveal is about being unable to complete the action, not showing that you meet the requirements for the action.  The one on Search definitely applies to what you exchange for, but not necessarily the other end.

I think they should be revealed, but I don't see the rule to back it up.

Im not sure if this is codified in the rules anywhere but, I've always thought that any time a specific card type is specified on an ability then it must be demonstrated that the cards requiring types fulfill the criteria to complete the ability. (I.e. revealing the good card to be exchanged and the good card exchanged for with Angel from the altar to show that they were indeed both good cards) Under that logic depending how the flood survivor exchange is ruled I could see someone exchanging an unrevealed card for 2 flood survivors but have to reveal if trying to utilize the of matching brigade clause.
 
I'm pretty sure most judges would rule supporting the reveals to avoid cheating but if it's not in the REG then this might be an assumed rule. The Noah exchange for 2 flood survivors though might be debatable altogether but that's more due to the nature of the (or 2 flood survivors) clause.