Entrance reducers in robbing season — do your strong hives keep them on too, or only the weak ones?

Third year in Uppsala, five hives. After watching a neighbour's yard get robbed out last week I've reduced everything — but now I'm doubting myself on the two really strong colonies. They're boiling with bees, and with the reducer on the smallest opening there's a permanent traffic jam of foragers at the entrance plus fanning lines trying to move air on warm days. Part of me says a hive that strong defends a full entrance just fine and I'm only hurting ventilation and foraging. Other part says robbing season is robbing season and one bad afternoon can flip even a strong hive. What's your actual practice in August — reducers on everything regardless, or sized to colony strength?