But you can choose to enter games that are only against your friends - I do every week. (There's nothing physically keeping a stranger from joining our game, bu

But you can choose to enter games that are only against your friends - I do every week. (There's nothing physically keeping a stranger from joining our game, but since they don't know the link, and we all enter as soon as one of us creates the contest and sends us all the link, it's unlikely.) OK, I also enter other games, but in those, I typically go for the games that are small, and almost filled, so I can look at the list of other players and only enter if there are no very experienced players there.