I personally don't agree with FACS rules and I know there is many many more people within Australia and abroad that don't either.
If a child is murdered, sexually assaulted, beaten, missing etc etc isn't it within the right of the child/ren to have a thorough open slather investigation, like what would happen if the same happened to a non foster child. Why should foster parents have special treatment, it's just a cover up because it's within a government body. It's the same with shonky police, politicians etc etc, they are all protected if they do wrong.
The safety of WT's sister is obviously of no great concern, for FACS or LE as many people know who the ff are, where they live work etc etc. So if it's all about protecting the sister 100% then why haven't they moved or have her placed with different carers so her whereabouts aren't known to the public.