The U.S. government has focused on the threat of liquid explosives since at least 1995.

NPR: It's Hard to Spot a Liquid Threat to Airline Safety

The following year, in 2006, U.K. authorities interrupted a plot to bomb trans-Atlantic airliners using liquid explosives carried in bottles.

WSJ: A Killing Puts U.K. on Guard for Terror

Meanwhile, what similar liquid-scanning technology has the TSA adopted in the six years since a would-be terrorist tried to blow up a plane with liquid explosives?

FORBES: Want To Carry Drinks Through Airport Security? This Machine Could Let You.

The British Crown Prosecution Service said it was a plot -- involving liquid explosives hidden in soft drink bottles -- that could have been pulled off.

CNN: Three guilty in bombing campaign plot

It's the same kind of trade-off TSA implicitly provided when it ordered us to take off our sneakers (to stop shoe bombs) and to chuck our water bottles (to prevent liquid explosives).

WSJ: Noah Shachtman: Has Airport Security Gone Too Far?

During the trial, prosecutors showed the jury an experiment which they said showed that a soft drink-size bottle filled with the kind of liquid explosives the men allegedly planned to use could have brought down a plane in mid-flight.

CNN: Three guilty in bombing campaign plot

On 10 August 2006, authorities in the United Kingdom uncovered an alleged plot to sabotage as many as 10 US airliners travelling from the UK to the USA, reportedly by using liquid and gel based explosives.

BBC: Short debate: The right to breathe