Movie theatre etiquette?

The most stressful thing about going to the movies is finding a seat with your whole group together. Because if your anything like me you will plan to leave in order to get there half an hour before.... and ends up getting there two minutes before the movie starts. This means that here are literally no seats left together. And every once in a while there is the perfect amount of seats except there is ALWAYS one person that is splitting them into two groups. Now if this person would just slide to the end of the row you could all sit happily together. But this one person always feels so entitled to this particular seat just because they got there BEFORE you!! And honestly it's for their benefit because your friends are gonna be talking over him/her for the entire movie. But these types of people can't even find the kindness in their hearts to make room for their temporary movie theatre buddies!!!