XD
If I had read closer I woulda answered my own question:
"You can cast one vote for the stage you want to play. A stage is chosen by lottery from among those voted on by the players.
Also, the items that are turned off in the item switch are also determined by lottery."
So it seems all the players choose items... and then it selects some of those items for the brawl... so if no one chooses items then no items can be chosen at random...
Also...
OPTIONS... Maybe you choose stock etc in here... and then go onto the next screen which is:
So perhaps it matches you up with people with similar or identical settings?