I actually thought the same thing at one time. lol I had a few "incompatible" couples that gave me fits having kids and they would always sit at opposite ends of the table, if I dropped them before I seated the kids.

I haven't compiled stats on it, but I did play around with where I dropped them and found that sometimes you can drop them on a certain stool (rather than the table) and they will sit on that stool. Of course, having kids in the house means there are fewer available seating places and they may end up sitting next to each other whether they want to or not.

So, I don't know if there's anything to the theory or not, but I do cringe when I have a brand new couple sit so very far apart. hehe