We get a few calls about this, pretty much all from people who want to have a quiz as part of their gala dinner (i.e. they want to have buzzer buttons on every table).
This is a fine idea in theory, but the reality (we've done it several times so have 'real' experience) is not quite as anticipated...
We deal in capturing who answered first; simply put, you press the fastest, you win.
If you spread your contestants around a room (where, having buzzed in, they get time to think about their answer before you can get a light and/or a mic to them), it becomes a whole different ball-game.
In our opinion, if you want to do this kind of thing, then you should either use a multiple choice wireless system from QuizTime, or use us, for a multi-round quiz contest (with teams from each table coming to the stage).