At the pre-releases in the past I have seen a couple of people playing a theme deck tournament.
However since I moved to Texas, no one has done this. The person that does the pre-releases does
sell the theme decks after the regular tournament (for $10 each).
I guess more people are interested in just getting the cards "early". In fact quite a few people just
come to get the cards, and then leave (or drop after a couple of rounds). Personally I never figured out
why they bother if they are not going to play in the full tournament.