Another E-Ticket nightmare: a couple of years ago at O'Hare, the United computer system was down for several hours. At some gates, only passengers with paper tickets were allowed to board their flights. E-Ticket people were left behind. This was at a time when probably less than 10% of the tickets were E-Tickets, but the problem was very real to the passengers carrying only printed copies of their itinerary. This is I hope a rare event, but it illustrates some of the weaknesses of the E-Ticket system.