Double Strollers

The other day I was sitting in Starbucks across from the Vancouver Library (as featured in Battlestar Galactica on "Cylon Occupied Caprica"), when I saw a woman pushing a stroller with 2 kids. It wasn't one of those wide strollers, but rather there was a front and a back. So it made me wonder if the front seat or the back seat is the preferred seat? Do they fight about who gets to sit in which seat? Just thinking about that made me happy I don't have kids.