On the one hand, I could see why a tournament
would not want to invite VP. In the biggest of all
DotA tournaments, VP cheated flagrantly, trashed
personally the members of its admin (see long
rants by NS and Jolie), and repeatedly trashed the
tournament itself.
On the other hand, many people, myself included,
just like to watch them playing the game and
playing against the other great teams, regardless
of how little class and respect they show.
The manners of VP are obviously quite bad. That
reflects on the sport and it makes the tourney
look bad for advertizers. But not having them play
is worse for the fans, which are the key part for
touraments as a business.