Bruce Schneier points out on his blog
a proposal to use electronic randomizers at airport security checkpoints
. Schneier writes there:
"I've seen something like this at customs in, I think, India. Every passenger walks up to a kiosk and presses a button. If the green light turns on, he walks through. If the red light turns on, his bags get searched. Presumably the customs officials can set the search percentage.
Automatic randomized screening is a good idea. It's free from bias or profiling. It can't be gamed. These both make it more secure. Note that this is just an RFI from the TSA. An actual program might be years away, and it might not be implemented well. But it's certainly a start."
In this case, the proposal is for randomizers that direct passengers to particular conveyor-belt lines for screening.