- DI cancels the card text, but the canceled card was still played.
- DI doesn't supersede/replace the basic rules of the game, such as the limitations on action modifiers/reactions played by the same vampire in the same action. It is important considering the first point, since the canceled card was still played.
- Actions canceled as played didn't even 'start' (or more technically, never reached resolution, as LSJ pointed out), so they don't trigger NRA-like clauses. This ties with the second point, since the rules about non-repeatable actions are in the rulebook now.
- Check out card-playing restrictions on each card canceled, especially for limitations like "only one [card X] can be played per [turn/round/combat/game]"; the text has been canceled, but a second copy still has the text and the first copy was still played.
- "As played" means "as played (from hand in the normal fashion)" save explicit text on the contrary, so you can't DI/cancel a card brought to play via other means (such as "Vast Wealth" or "Concealed/Disguised Weapon"). So, you can DI a "Concealed Weapon" card but not the weapon, it is about to bring to play.
- This holds for "Sudden Reversal" as well: Cards are not replaced in the "as played" window, but rather wait until after they are played. Other card-moving effects (like all other effects, by default) are also unable to sqeeze into the "as played" window. The "as played" window for card X thus restricts all players to the cards they have in hand at the time the card X is played. Specifically, you cannot tap "The Barrens" or "Erciyes Fragments" to go fishing for a DI or a "Sudden Reversal" in response to the play of card X (although you could use a DI that was already on your Fragment).
Originally written by Fabio 'Sooner' Macedo and LSJ in the VtES Usenet Newsgroup on October 13th, 2006.