We had our main Christmas presents shortly before dinner was ready, which tended to be 2 to 3pm, so yes, restraint existed in our house, too. We did get the Santa presents at the end of the bed, so we had stuff to occupy us (Mum learned that a book in the stocking was a surefire way to keep me quiet for a bit
).
We also had our favourite places to sit at the table, and also in the living room, so rarely sat in someone else's seat.
This must have bee the case in ex's family too, as he and I carried on with sitting in our favourite places, and in the same seats at the table. I do this now with the DC. It's habit yes, but we all have different preferences.
Interestingly, we sit in different places when my dad and DBro come round for dinner