BEIJING — It seemed innocuous enough on the surface: The smooth-jazz musician Kenny G paid a surprise visit to a Hong Kong protest site on Wednesday, posing for photos with residents who are demanding the right to free elections.

He shared on Twitter the news that he was at the demonstration, along with a smiling photo showing a protest banner in the background.

But little is that simple here.

Kenny G is an icon in China, and his visit stirred up controversy and conspiracy theories on both sides of the political divide.

In one of the more inexplicable mysteries of Chinese culture, his 1989 saxophone ballad “Going Home” has for decades oozed from speakers across Chinese public spaces at closing time, setting off rapid exits by the masses. The song has no lyrics, yet somehow, when it is played in a mall, Chinese shoppers know what to do. They go home.