Image via WikipediaGenies are stuffed into bottles all the time...but I wonder why? Did Pandora use the last box? I guess the phrase "bottled up" is as close to the truth as I'm going to get.
What would a person stuff into a bottle and lock away? Not something with a great power they can use, that's for sure. It's something fearful. Things like forbidden desires and dark magic. Stuff you KNOW is wrong and yet you're tempted with anyway. (No wonder they stuffed Christina in there! She looks like jailbait in this video.)
So you put your former ally/scapegoat in a bottle and put a cork in it. It's not the genie's fault you can't control yourself, is it? I would be pretty pissed if I had to be stuck in a bottle. Hence, the bottled djinn vintage is usually....unhappy. How many stories are there about angry djinn and their masters? A bazillion? Hint: NO masters in my MS.
Actually, djinn can be bound to any object. Like the Horcrux idea, the object is a vessel for the spirit, and the object can be a person, as Harry demonstrates. You might say Harry is ma-voldemort...lol! (As opposed to majnoon which means crazy and translates to "with the djinn".)
So why would a djinn even get into such a bad situation? Curiosity. Our world is interesting to them and they get tangled up in it if they get too close to someone, or someplace. I have to stop here...or I'll get too far into my story. ;)