Its happened to me about half a dozen times... I always slip my wallet into my right front pants pocket, i have always hated putting anything in my back pocket. So it always falls between the seat and the center console.I know the feeling though... it sucks !
Do you have the obligatory photocopied document of all your credit/bank cards, handy?, front and back, with the correct phone numbers to call to cancel them in case it does fall into the wrong hands.. ?