I ran into this page on how to leave messages for those left behind after the Rapture.
An alternative method for today's Christians to communicate to those left behind on earth after the rapture is to simply post, in a highly visible location in the home, a message such as:So, if I read this right, they're going to be leaving notes for us in their own homes. I suppose this means that they've figured out that we'll be ransacking their houses and stealing all their crap after they're gone.
“I am writing this to you in the past. In your present time, the church (believers in Jesus Christ) has been raptured, and has been taken out of this world to be present with the Lord. You have been left behind. To gain eternal life and salvation, and to be with Jesus Christ, you must accept Jesus Christ as your saviour from sin and refuse to take the mark of the beast on your hand or forehead and refuse to worship the beast and his image or statue, even if it means you have to die.