In every judge call I've been involved so far, if a spell was illegal to cast, I've done a full rewind, including untap lands (ask for what lands where used for paying mana costs!! :) ). IMHO I can't see why this should be avoided in “simple cases”, tap Forest tap Swamp, Abrupt Decay your Mutavault, for example. And most players tap for mana BEFORE casting the spell: it seems to me that don't letting them untap the lands used for casting the spell is too harsh, even in Comp/Pro REL.

Edited Joaquín Pérez (April 23, 2014 06:58:00 AM)