The feeling that many of us believe to be love is usually lust. One can have feelings for another, but there is no definite concept of love. I do not believe that I or anybody else has ever experienced this thing called love that we are attempting to define. The reason love is so difficult to define is simply because it doesn't exist. I believe that people feel loyalty, and mistake it for love.
Love implies something higher than loyalty which nobody can explain because nobody has ever felt it.
The two teenagers that you mention may feel loyal to one another. However, they are certainly not in love. For young people to be so far away and still feel so close is more than loyalty. Loyalty is a moral value, but the force that keeps them together is more powerful than loyalty. It's absolutely nothing, oh wise and great Scottrates.