Where would lost earphones be?

Okay, so we were coming back from this festival and my sister was using my earphones on the way there. On our way home, she couldn't find them anywhere! We were positive they were in the car, and we've checked the car a lot of times. I'm beginning to give up hope on looking for them in the car, cause my mom did and she has really sharp eyes. One time, my dad lost his bose earphone rubber things and they were tiny right and my mom found them. She's amazing. But anyway, could they have been stolen? I've asked that question many times to my family but they just shrug and mumble " obviously not " and there wasn't any sign of damage on our car. And why would anyone want to steal earphones? well, mine were roxy and they were beautiful and matched my ipod perfectly. Omg i get side tracked. anyway, where do you think I should look for them? I really miss my pretty earphones!!!!!