Teachers who have (and leave) seating charts have their classes set up a certain way for a reason. They've been honing these configurations since the beginning of the school year. The three girls who can't be trusted to sit next to each other have been placed as far apart as possible, usually in opposing corners. If those girls were together chaos might ensue. So, when a sub enters the room, the first thing they try is to swap seats so that they can sit together. The savvy sub tries to prevent this from happening.
The weather around here just went from the 60s to the 90s in less than a week. The forecast was for 90 degree weather today, so I turned on the air conditioning early. The students complained. I didn't really care. I was right, and they'd figure that out eventually, but they were cold (insert whine here).
One girl just had to move. She was seated right underneath the air conditioning vent. It was too cold for her. But where was she going to sit? Right next to her friend, of course. No way.
And there was my dilemma. Rock: do not deviate from seating chart. Hard place: air conditioning vent. What to do? What to do?
We compromised (I allowed her to move one seat up from her usual spot). And it made no difference. Those girls? They talked to each other across the room anyway.