It's not like in real life where you have to have access to the actual promo cards to use them. The reasons that real life tournaments don't allow promo cards that have not yet been released in a set don't apply to OCTGN play.
And it's probably a good thing that octgn tournaments don't completely mimic real life ones. So octgn has full card access in game, but it lacks the face-to-face interaction, setting and overall feel of real life tournaments. Swiss has an advantage over single elimination in tournaments because more people get to play more games, so luck with matchups plays less of a role, not to mention that if player A beats player B and player B beats player C that doesn't mean that player A will beat player C, and single elimination doesn't allow us to find out, and possibly even creates the illusion that we already would know the outcome of that hypothetical matchup--that player A is better at the game than player C, since they progressed farther in the tournament. Unfortunately, swiss tournaments just don't work on OCTGN, and single elimination has the added advantage of greater tension and drama for viewers.
Some other differences between octgn play and real life include the fact that octgn is worldwide while real life mage wars tournaments are not, being much more limited by geography, and for the most part only being held in conventions in the US. I'm really hoping that we eventually get some mage wars computer games that work on both mac and pc without having to go through the long, complicated, and difficult process of installing wine and getting it to work, which is arguably impossible for a layperson with no computer programming expertise, even WITH all the instructions. Believe me, I tried, and so did my sister. This is one of the major barriers that prevents her from playing against people other than me.
Anyways, just thought I'd give my two V'tar while we're on the subject. Also, I'm not positive whether I'll be able to participate or not, since it will be during summer semester and I have a biology class I will be taking then. Granted, the tournament is on the weekend, but I have no idea yet what my homework load will look like. Should I just sign up for it now and then cancel my participation later if it doesn't work out? I probably won't know until maybe a few weeks before hand.