Mobile Police say they’ve had about 38 robberies since September 20th. These numbers run counter to seasonal crime trends. 18 of the 38 robberies since September 20th have been business robberies. Police don’t have an explanation--the spike is unusual given conventional wisdom is crime goes down once school starts.  “We've had a fairly inactive summer as far as robberies are concerned and now that school has started things have picked up,” says Officer Chris Levy with the Mobile Police Department. Levy says business owners can protect themselves by making sure their…