If you had said 10% then I would be suggesting the ID checks that sometimes come up on bookings, full details in the main thread in the Forum Dashboard, "Why can't I check-in online". That thread also has other factors listed in it, such as the way you get ticketed (via a corporate account?) or particular routes. For the second part of the quote, all I can say is that if the IT was as bad as your experiences, the number of OLCI threads we get in this forum would probably go the roof, so it may be worth going into more forensic detail the next time it happens.