My kids knew better than to open a single present until DH and I had coffee and were sitting down in the living room. Then DH would pass out the presents. Christmas at our house was always AT our house; we might go see the grands or other folks, but usually not. Mostly because everyone came to our house for Christmas dinner - family, friends, co-workers - and I'd already have the turkey or ham on, pies baking; and many times one or both of us had to work either Christmas Eve or Christmas Day.
But there is no way any adult would tell us what the rules were in our own home, or try to snatch and grab like greedy children. Period.