Btw here are some reasons that he/she might be (Busy,Offline,Lazy,Trip,Marriage,Party,Accident,birthday,Tenshion,)
so my suggestion is it should not be an imortant step for those who dont want to re-enter their eth address
Everyone will have up to 45 days at their disposal to complete the form and withdraw their earned tokens.
We prefer to use this approach rather than hear them saying they sent us their coinbase/poloniex/bittrex/etc address and lost the tokens. 90% of the emails we receive are about this, so if 9 in 10 people filled a wrong address, it's something we will ask people to do.