For a long time airlines has estimated the weight of passengers to determine how much fuel is required for a flight. Now a bunch of boffins have come up with a way to weigh passengers discreetly so airplane fuel can be tailored to the flight [news.com.au]. This system would of course keep this data confidential.
I wonder if they'll add an autocharge to the passenger's credit card if they are overweight or a refund if they are under the average weight.