I don't know enough about what SE has said about the surname implementation, so I'm not offering an argument, just a fact.
In EQ2, we had surnames also, you didn't get to pick one until lvl 20. That being said, given (first) names had to be original. Your surname was just something to add something to your character's name, or to denote the guild you were in on screen.
Suppose you had a friend with a character named Lubriderm Handlotion. If you a tell to Lubriderm, that tell would get through. If you sent a tell to Handlotion, it would not. If you sent a tell to Lubriderm Handlotion, it would not either.
Before we know exactly how they are going to implement surnames, we should just calm down.