Substance or Accident?

Today US and Asian stock markets fell and wavered in fear before the meeting of the US Federal Reserve, making clear the anxiety of the markets regarding a US rate hike. The question as it appears to me though is, did the fear and retrenchment accidentally send a message to the Fed, or was the fear and retrenchment the message itself? Standing from the outside, the substance and accident of the phenomenon cannot be readily differentiated.