Second Tradition: Domain vs Form of Mist

I couldn't find an official answer (only groups.google.com/d/topic/rec.games.trading-cards.jyhad/uV4jT0IZfeU/discussion)

How long does the +2 intercept effect applies when Second Tradition is played by a tapped vampire?

The text is likely ambiguous:

"to untap and attempt to block with +2 intercept"

The +2 intercept bonus is linked to the block attempt, but nothing says it lasts for the duration of the action.

So if the vampire blocks, and the acting vampire plays Form of Mist*, one could say that if the blocking minion plays a wake effect, the +2 intercept is lost.

*: there could be already a loophole here since one could consider the blocking minion has already lost his +2 intercept, and therefore Form of Mist can't be played.

This concerns also Guard Duty, Open Dossier, Read the Winds, Under Siege.

The real thing that interests me is: how can it last for the duration of the action?

Is there a better way to formulate this? For instance: "Also usable by a tapped prince or justicar, even if intercept is not yet needed, to burn a blood to untap and attempt to block with +2 intercept {for the current action}".

FrançoisV wrote:

From the online rulebook :

Note that all modifications made to a minion's stealth or intercept remain in effect for the duration of the action. Increased stealth and intercept return to normal after the action is resolved.

Does it mean that Backways' text is superfluous?

Name: Backways
Cardtype: Master
Clan: Gangrel
Cost: 2 pool
Master: unique location.
Tap to give a Gangrel you control +1 stealth for the current action.

Same thing with The Anarch Free Press, Anarch Railroad, Aranthebes, Bowl of Convergence, Carnivale, Changeling Skin Mask, Channel 10, Club Zombie, Corpse Minion, Elysian Fields, Enid Blount, Fortune Teller Shop, The Labyrinth, London Evening Star, Tabloid Newspaper, Malajit Chandramouli, Marciana Giovanni, Investigator, New Moon Sigil, Opium Den, ...

(but curiously not KRCG News Radio:
Name: KRCG News Radio
[Jyhad:U, VTES:U, CE:U, LoB:PA, LotN:PG, KoT:U/PB]
Cardtype: Master
Cost: 2 pool
Master: unique location.
Tap to give +1 intercept to a minion you control, or tap this location and burn 1 pool to give +1 intercept to a minion controlled by another Methuselah.
)

What about The Horde, Census Taker, Miguel Santo Domingo that grand a temporary +X bleed or +X votes?

I forgot my previous post. Thanks!