Having said that, what is stopping your opponents from picking the answer for you? I would assume all the answer buttons would have to be the same.
Yeah, that happens sometimes during a heated game. But then you get to punch the button happy person.

You could always just only map the buzz in buttons.
You can usually find the Buzz controllers on sale for $20 or less. Cheap, saves a lot of contsruction time and looks/feels great.
I also have a small Gyration wireless keyboard handy to pass around when needed. Having the BUZZers sure beats everyone hunched over 1 keyboard.
BTW, I map the extra 4th controller as the screw button. Sits on the table until needed and then the answer keys are the player to screw. Easier then finding the S on the keyboard. Saves wear and tear on the S key in "Jack The Ride" multi-screw.
It is really too bad that there is no driver to get the Microsoft Scene-it controllers to work. Wireless would be way cooler.
D.