Occasionally there is a tournament that fills just a few hours after its creation. Often the tournament creator then creates another tournament with the same parameters.
I think it would be good if those that were already playing in the initial tournament were prevented from entering the new one.
The Xmas 2006 Grand Split tournaments (I & II) spring to mind as an example. There are 6 players that have chosen to play in both tournaments. I'm not saying they're wrong to have done this, simply that it was 6 less places available to the others who may have wished to enter.
While I'm on the subject can we please have a Xmas 2006 Grand Split tournaments III? Both I and II filled quickly, I'm sure III will too.