Warrego is clearly the more conservative company and they...

Warrego is clearly the more conservative company and they obviously have sufficient data to interpret the water as a gas-water-contact rather than a local perched water leg. Apart from Irwin-1 which hit water at Kingia (it was drilled for the Wagina reservoir), no other Kingia/High Cliff well has encountered water.
If it does turn out to be a GWC, then is pins the volumes and reduces the risk on WE. However, as I suspect, STX won't like a GWC at 4630mTVDSS because it will have an impact on South Erregulla. I'll need to go over the SE releases to work out what is means for SE if they have indeed hit water.
As for trusting STX over WGO? I'll let you decide but this is the same team that sold you all on the Jaws project