With SCEA dodging the question by European gamers in regards to Warhawk's release date, and in addition to many UK retailers over the past week scheduling it for late 2007, it is pretty much all but confirmed that despite Icognito's promise - Warhawk will not be released worldwide on August 28th.
Now several UK retailers have specified a firm date of September 14th. Although this is not confirmed by SCEE, it seems very likely to be accurate.