What they're unsure about is exactly what might happen?
Japanese toilets, a source of pride to their owners and amazement to everybody else, often include microprocessor systems, which raise the pedestal to a convenient height or control bidet functions.
Brian Randell, of Newcastle University's department of computing science, said that he regularly visits a research lab in Japan where a toilet includes digital controls with displays of date and time, a sure-fire pointer to millennium bug hazards, which can affect any chip that relies on the date. "Guessing how they could go wrong is impossible - though fun," said Professor Randell.
Japan's advanced toilets already have been implicated in a number of house fires, caused by water leaking on to electrical contacts used to heat water for the bidet. Or, as the Japanese newspaper Mainichi Shinbun put it, "Many fires by toilet: it smells and your bottom is on fire".