Some of the passengers pulled out cell phones during the flight and appeared to be trying to pass the cell phones to other passengers, a U.S. government official said.
In addition, some passengers unfastened their seatbelts while the light requiring they be fastened was still illuminated, the official said.
That was enough for U.S. air marshals aboard the DC-10 to break their cover. Flight attendants ordered the passengers to heed the orders of the marshals, the official added.
There was no intelligence indicating the flight was at risk, and authorities are still evaluating how much of a threat the passengers posed, officials said.
The passengers who were arrested were looking into plastic bags and were busy with their cell phones...
http://www.cnn.com/2006/WORLD/europe/08/23/schiphol/
Good for the air marshalls
That is exactly what they are trained to do and there is no room for horseplay on planes anymore.