Now that you mention that I believe you are right. Last week I was out with a friend doing a field shoot. There weren't all that many birds flying but when 2 or 3 would come our way to the decoys they came in from our left. Because I was on the right of my buddy, we came to an agreement that I would shoot at the lead bird and he'd take a shot at the next one coming in from behind.
Let's just say I was calling myself "Hen Boy" by the end of our shoot. There just weren't enough birds to just pick out green heads, otherwise we would only have gotten to shoot at half the birds we eventually got because obviously we would have rather had all green heads.
https://i.imgur.com/aaTjeVs.jpg