Quote from FMPONEIts pretty terribly simple then, certainly no fault of the pilots.
My dad says one of the first things he learnt in the RAF was that if you see a target with what you even think is friendly signal on it then you do not even think about firing on it.
Especially considering now that its being very widely reported that aside from the Orange panels on the roof being displayed they also had Union Jacks on them.
Dara O Brian summed it up nicely on "Mock The Week" a while ago:
QuoteBritish soldiers in Iraq are being shot at on a daily basis, although obviously it'll get much safer when the Americans leave and it's only the Iraqis firing at them