Originally Posted by
SkyTeam777
Is this something that you simply print out and bring with you? or do you have to mail your passport to them?
You can print it out if you like but that won't do you any good. If your ETA (or visa) is not valid, the airline won't put you on the plane - if they fly you in without a valid ETA/visa, they'll be fined and made to fly you straight back again.