I think, when the rapture occurs and all those millions of people disappear from the earth, they will leave behind wallets and purses.  Those people left behind will find this treasure trove, scooping up drivers licenses, credit cards, etc., leading to the biggest identity theft crisis in history.  The government, banks, and retailers will have to deal with the problem fast so chip implants might be the answer to prove you are who you are when you present a credit card which might have been picked up from a pile of clothes left when the rightful owner went to be with Jesus.  And the chip implant might be the "mark".  Let's all "pray we may be accounted worthy to escape all these things..."