Dunno...I was fishing....
However...
http://avherald.com/h?article=42ba1c55&opt=0
“A Delta Airlines Boeing 747-400, registration N675NW performing flight DL-620 from Tokyo Narita (Japan) to Minneapolis,MN (USA) with 407 people on board, was enroute about one hour into the flight, when two male passengers were observed carrying a plastic bag containing some liquid into a lavatory raising concerns with the crew. The captain ordered the two passengers to be detained and decided to return to Tokyo for a safe landing. The passengers were taken into custody by Tokyo police.
Laboratory tests revealed the liquid was not dangerous at all identifying the liquid as urine.
The flight was cancelled.”
This does not make sense? Why were they carrying urine? A false run?