Database: food_inspection
Question: Among the violations in 2016, how many of them have unscheduled inspections?
SQL: SELECT COUNT(T2.business_id) FROM violations AS T1 INNER JOIN inspections AS T2 ON T1.business_id = T2.business_id WHERE STRFTIME('%Y', T1.`date`) = '2016' AND T2.type = 'Routine - Unscheduled'