JMC man makes some very valid points - particularly in relation to cashflow.
The traditional LCA model encourages early booking in the way the yields are managed. There is nothing with the NOW fare structure to encourage anyone to book early.....that's a lot less cash sitting in the bank on a day-to-day basis, and we all know that in this business even the most successful companies work on very narrow margins, so this cashflow situation will have a major impact.