Around here, you can get robbing whether you feed or not, and whether you feed in the hive or out. A dearth is a dearth and when it last 7 or 8 months, you do what you have to to keep the bees alive. In my opinion, if you have to feed, it doesn't really matter how you do it. Any method is possible to start robbing. I haven't seen any robbing as a result of feeding, either honey from cutouts or from syrup. My OB hive would be the first to get hit. I would start feeding late in the day if you haven't fed before. Once they have some syrup in the hives to protect, they are far less likely to start robbing. Mine emptied the feeder twice in 4 hours.