When the top guy leaves, that signals to the rank and file it's OK to leave. It tends to look bad when the rank and file leave before the boss. It's an extremely well understood social signal (whether you buy into that or not, doesn't matter. It's the signal).
So there is a strong understanding of this in aware managers - they will leave in the 4:30-5:30 bracket, so their employees don't feel compelled to work long hours.
When the top guy leaves, that signals to the rank and file it's OK to leave. It tends to look bad when the rank and file leave before the boss. It's an extremely well understood social signal (whether you buy into that or not, doesn't matter. It's the signal).
So there is a strong understanding of this in aware managers - they will leave in the 4:30-5:30 bracket, so their employees don't feel compelled to work long hours.