So, if Terror in Venice is released at Gencon like most are expecting then it WILL be legal to play in the North American championship according to the FAQ. For this reason I almost think that it wont be available at Gencon. Do you think that Fantasy Flight would throw that many cards into the card pool 2 days before a big tournament?

Nope. Consider the other LCGs, e.g. Star Wars: Cards from the 'Battle of Hoth' (scheduled for release in August) will not be legal, although it would have been released 'in time'.

Only potential issue is the Star Wars faq explicitly states Battle of Hoth is not legal.

The Battle of Hoth will not be legal for the

North American Championship tournament at Gen Con

2013.

However the Cthulhu faq does says this:

In North America, all cards are Tournament legal upon release

So it's either an oversight, they know Venice won't be out in time, or they want it legal even that close to the tournament.

Not really worth worrying about it in my opinion, until we actually see it released.

I'll just go with whatever happens. My main concern is that I want new cards as soon as possible. Whether they're legal at Gencon is secondary to that. I doubt anyone's going to make up a whole new deck based on untested cards right on the spot, so at most we might see 1-2 cards swapped into of someone's deck they already had.