Qantas are big boys and I'm sure they can cope. If investors think $4.20 is a good buy then they'll go for it. If not, QF will have to wait but given the institutional enthusiasm the other week, any shortfall could easily be made up via another institutional placement.
Who knows if SQ meant to inflict damage on QF? If they meant to, they should have acted a couple of weeks ago and lowered the book build price.
The Australian sharemarket has slipped over the past week and the continuing problems in the US economy means that QF's international ops will take even longer to come back. All these things are weighing on the share price. I somehow doubt the re-run of a story thats been around for 10 months is the only cause of the QF slump.