That's a bit of a nuisance, thanks for the update.
The map they've provided appears to show the closure to the north of Brett's Road; in your opinion would it be possible to access it using an ordinary 2WD from the south, using Condomine River Road from Killarney across to the Head Road? I'm not familiar with the road. It's made more complicated by the fixed border closures at White Swamp Road and Carney's Creek.
I suppose they've decided to take advantage of the decreased traffic.