I have never had a problem with E-tickets within the US. I have paid for many tickets with my credit card for family members and friends and there has never been an identifcation problem at check-in. I find E-tickets take one less hassel out of "where did I put the paper tickets?". Alaska gives you a 500 mile bonus everytime you check in using their e/tk check in counters. I would agree with Rudi not to use E tickets on internationl segments. The only time you can get an E-ticket for international flights is if your trip is all on the same airline (AA and CP might be the exception) and only to certain countries. E tickets on international trips have a long way to go before they will become as common as domestic E-ticketing.